diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..0a722d7
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use nix;
diff --git a/.gcloudignore b/.gcloudignore
new file mode 100644
index 0000000..f0f21f0
--- /dev/null
+++ b/.gcloudignore
@@ -0,0 +1,6 @@
+.git
+.DS_Store
+*.pyc
+*.nix
+.envrc
+#!include:.gitignore
diff --git a/.gitignore b/.gitignore
index 0d20b64..0b27afb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,3 @@
 *.pyc
+.direnv
+__pycache__
diff --git a/Makefile b/Makefile
index fc5af25..1fcbacf 100644
--- a/Makefile
+++ b/Makefile
@@ -1,13 +1,19 @@
 .PHONY: serve test_deps test check appcfg-update deploy
 
 serve:
-	dev_appserver.py --log_level=debug . --host=0.0.0.0
+	honcho start
 
 test_deps:
 	pip install -r requirements-dev.txt
 
-test check:
-	python -m unittest discover -p '*_test.py'
+test:
+	pytest
+
+typecheck:
+	pyright
 
 appcfg-update deploy:
-	gcloud app deploy --project "${APP}"
+	gcloud app deploy
+
+create-indexes:
+	gcloud datastore indexes create index.yaml
diff --git a/Procfile b/Procfile
new file mode 100644
index 0000000..f3350d9
--- /dev/null
+++ b/Procfile
@@ -0,0 +1,2 @@
+datastore: gcloud beta emulators datastore start
+web: $(gcloud beta emulators datastore env-init); python main.py
diff --git a/app.yaml b/app.yaml
index c4cdfdb..218c01e 100644
--- a/app.yaml
+++ b/app.yaml
@@ -1,7 +1,15 @@
-runtime: python27
-threadsafe: yes
-api_version: 1
+runtime: python310
 default_expiration: "365d"
+app_engine_apis: true
+
+# Slack has a very short timeout on API callbacks, so we need to keep at least 1
+# process running for it
+automatic_scaling:
+  min_instances: 1
+
+# min_instances requires warmup requests to work
+inbound_services:
+  - warmup
 
 handlers:
 - url: /static
@@ -13,23 +21,13 @@ handlers:
   upload: static/favicon.ico
 
 - url: /admin/.*
-  script: snippets.application
+  script: auto
   login: admin
+  secure: always
 
-- url: .*
-  script: snippets.application
-
-skip_files:
-- .git
-- .DS_Store
-- .*.pyc
+- url: /.*
+  script: auto
+  secure: always
 
 builtins:
 - remote_api: on
-
-libraries:
-- name: jinja2
-  version: "2.6"
-# This also brings in webapp2_extras:
-- name: webapp2
-  version: "2.5.1"
diff --git a/conftest.py b/conftest.py
new file mode 100644
index 0000000..15c726f
--- /dev/null
+++ b/conftest.py
@@ -0,0 +1,35 @@
+"""conftest - loaded automatically by the pytest runner"""
+
+from unittest.mock import MagicMock
+
+from google.cloud import ndb
+from google.cloud.ndb import _datastore_api
+from InMemoryCloudDatastoreStub.datastore_stub import LocalDatastoreStub
+import pytest
+from _pytest.monkeypatch import MonkeyPatch
+
+
+@pytest.fixture(autouse=True)
+def ndb_stub(monkeypatch: MonkeyPatch) -> LocalDatastoreStub:
+    stub = LocalDatastoreStub()
+    monkeypatch.setattr(_datastore_api, "stub", MagicMock(return_value=stub))
+    return stub
+
+
+@pytest.fixture(autouse=True)
+def ndb_context(init_ndb_env_vars):
+    client = ndb.Client()
+    with client.context() as context:
+        yield context
+
+
+@pytest.fixture(autouse=True)
+def init_ndb_env_vars(monkeypatch: MonkeyPatch) -> None:
+    """Set environment variables for the test ndb client.
+
+    Initializing an ndb Client in a test env requires some environment variables
+    to be set. For now, these are just garbage values intended to give the
+    library _something_ (we don't expect them to actually work yet)
+    """
+    monkeypatch.setenv("DATASTORE_EMULATOR_HOST", "localhost")
+    monkeypatch.setenv("DATASTORE_DATASET", "datastore-stub-test")
diff --git a/cron.yaml b/cron.yaml
index f20cfb1..c526358 100644
--- a/cron.yaml
+++ b/cron.yaml
@@ -2,7 +2,7 @@ cron:
 
 - description: snippets chat -- early reminder to write snippets
   url: /admin/send_friday_reminder_chat
-  schedule: every friday 16:00
+  schedule: every friday 13:00
   timezone: US/Pacific
 
 - description: snippets email -- reminder to write snippets
diff --git a/main.py b/main.py
new file mode 100644
index 0000000..65537a1
--- /dev/null
+++ b/main.py
@@ -0,0 +1,32 @@
+#!/usr/bin/env python3
+
+import snippets
+
+import google.appengine.api
+import google.cloud.ndb
+
+
+class NDBMiddleware:
+    """WSGI middleware to wrap the app in Google Cloud NDB context"""
+    def __init__(self, app):
+        self.app = app
+        self.client = google.cloud.ndb.Client()
+
+    def __call__(self, environ, start_response):
+        with self.client.context():
+            return self.app(environ, start_response)
+
+app = snippets.app
+app.wsgi_app = google.appengine.api.wrap_wsgi_app(app.wsgi_app)
+app.wsgi_app = NDBMiddleware(app.wsgi_app)
+
+
+if __name__ == '__main__':
+    # This is used when running locally only. When deploying to Google App
+    # Engine, a webserver process such as Gunicorn will serve the app. You
+    # can configure startup instructions by adding `entrypoint` to app.yaml.
+    #
+    # To control listening IP and port, set SERVER_NAME in the environment.
+    # e.g. SERVER_NAME=127.0.0.1:8080
+    # Default is to listen on 127.0.0.1:5000
+    app.run(debug=True)
diff --git a/models.py b/models.py
index c6f0f10..427ec33 100644
--- a/models.py
+++ b/models.py
@@ -2,7 +2,7 @@
 import hashlib
 import os
 
-from google.appengine.ext import db
+from google.cloud import ndb
 from google.appengine.api import users
 
 
@@ -21,54 +21,55 @@
 # support that later.
 
 
-class User(db.Model):
+class User(ndb.Model):
     """User preferences."""
-    created = db.DateTimeProperty()
-    last_modified = db.DateTimeProperty(auto_now=True)
-    email = db.StringProperty(required=True)           # The key to this record
-    is_hidden = db.BooleanProperty(default=False)      # hide 'empty' snippets
-    category = db.StringProperty(default=NULL_CATEGORY)  # groups snippets
-    uses_markdown = db.BooleanProperty(default=True)  # interpret snippet text
-    private_snippets = db.BooleanProperty(default=False)  # private by default?
-    wants_email = db.BooleanProperty(default=True)     # get nag emails?
+    created = ndb.DateTimeProperty(auto_now_add=True)
+    last_modified = ndb.DateTimeProperty(auto_now=True)
+    email = ndb.StringProperty(required=True)              # The key to this record
+    is_hidden = ndb.BooleanProperty(default=False)         # hide 'empty' snippets
+    category = ndb.StringProperty(default=NULL_CATEGORY)   # groups snippets
+    uses_markdown = ndb.BooleanProperty(default=True)      # interpret snippet text
+    private_snippets = ndb.BooleanProperty(default=False)  # private by default?
+    wants_email = ndb.BooleanProperty(default=True)        # get nag emails?
     # TODO(csilvers): make a ListProperty instead.
-    wants_to_view = db.TextProperty(default='all')     # comma-separated list
-    display_name = db.TextProperty(default='')         #  display name of the user
+    wants_to_view = ndb.TextProperty(default='all')  # comma-separated list
+    display_name = ndb.TextProperty(default='')  # Display name of the user
+    slack_id = ndb.StringProperty(default='')  # Slack member ID (not nickname!)
 
 
-class Snippet(db.Model):
+class Snippet(ndb.Model):
     """Every snippet is identified by the monday of the week it goes with."""
-    created = db.DateTimeProperty()
-    last_modified = db.DateTimeProperty(auto_now=True)
-    display_name = db.StringProperty()        # display name of the user
-    email = db.StringProperty(required=True)  # week+email: key to this record
-    week = db.DateProperty(required=True)     # the monday of the week
-    text = db.TextProperty()
-    private = db.BooleanProperty(default=False)       # snippet is private?
-    is_markdown = db.BooleanProperty(default=False)   # text is markdown?
+    created = ndb.DateTimeProperty(auto_now_add=True)
+    last_modified = ndb.DateTimeProperty(auto_now=True)
+    display_name = ndb.StringProperty()        # display name of the user
+    email = ndb.StringProperty(required=True)  # week+email: key to this record
+    week = ndb.DateProperty(required=True)     # the monday of the week
+    text = ndb.TextProperty()
+    private = ndb.BooleanProperty(default=False)       # snippet is private?
+    is_markdown = ndb.BooleanProperty(default=False)   # text is markdown?
 
     @property
     def email_md5_hash(self):
         m = hashlib.md5()
-        m.update(self.email)
+        m.update(self.email.encode('utf-8'))
         return m.hexdigest()
 
 
-class AppSettings(db.Model):
+class AppSettings(ndb.Model):
     """Application-wide preferences."""
-    created = db.DateTimeProperty()
-    last_modified = db.DateTimeProperty(auto_now=True)
+    created = ndb.DateTimeProperty(auto_now_add=True)
+    last_modified = ndb.DateTimeProperty(auto_now=True)
     # Application settings
-    domains = db.StringListProperty(required=True)
-    hostname = db.StringProperty(required=True)           # used for emails
-    default_private = db.BooleanProperty(default=False)   # new-user default
-    default_markdown = db.BooleanProperty(default=True)   # new-user default
-    default_email = db.BooleanProperty(default=True)      # new-user default
+    domains = ndb.StringProperty(repeated=True)
+    hostname = ndb.StringProperty(required=True)           # used for emails
+    default_private = ndb.BooleanProperty(default=False)   # new-user default
+    default_markdown = ndb.BooleanProperty(default=True)   # new-user default
+    default_email = ndb.BooleanProperty(default=True)      # new-user default
     # Chat and email settings
-    email_from = db.StringProperty(default='')
-    slack_channel = db.StringProperty(default='')
-    slack_token = db.StringProperty(default='')
-    slack_slash_token = db.StringProperty(default='')
+    email_from = ndb.StringProperty(default='')
+    slack_channel = ndb.StringProperty(default='')
+    slack_token = ndb.StringProperty(default='')
+    slack_slash_token = ndb.StringProperty(default='')
 
     @staticmethod
     def get(create_if_missing=False, domains=None):
@@ -79,12 +80,12 @@ def get(create_if_missing=False, domains=None):
         are initialized with the given value for 'domains'.  The new
         entity is *not* put to the datastore.
         """
-        retval = AppSettings.get_by_key_name('global_settings')
+        retval = AppSettings.get_by_id('global_settings')
         if retval:
             return retval
         elif create_if_missing:
             # We default to sending email, and having it look like it's
-            # comint from the current user.  We add a '+snippets' in there
+            # coming from the current user.  We add a '+snippets' in there
             # to allow for filtering
             email_address = users.get_current_user().email()
             email_address = email_address.replace('@', '+snippets@')
@@ -93,7 +94,7 @@ def get(create_if_missing=False, domains=None):
             # you accessed the site on here.
             hostname = '%s://%s' % (os.environ.get('wsgi.url_scheme', 'http'),
                                     os.environ['HTTP_HOST'])
-            return AppSettings(key_name='global_settings',
+            return AppSettings(id='global_settings',
                                created=datetime.datetime.now(),
                                domains=domains,
                                hostname=hostname,
diff --git a/nix/sources.json b/nix/sources.json
new file mode 100644
index 0000000..70e5847
--- /dev/null
+++ b/nix/sources.json
@@ -0,0 +1,14 @@
+{
+    "nixpkgs": {
+        "branch": "nixos-22.11",
+        "description": "Nix Packages collection",
+        "homepage": null,
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "eef86b8a942913a828b9ef13722835f359deef29",
+        "sha256": "1ig0mc7f2n1pxzd5y9m4vz38zp515vn5s576kwhkhj62zdw99p2v",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/eef86b8a942913a828b9ef13722835f359deef29.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    }
+}
diff --git a/nix/sources.nix b/nix/sources.nix
new file mode 100644
index 0000000..fe3dadf
--- /dev/null
+++ b/nix/sources.nix
@@ -0,0 +1,198 @@
+# This file has been generated by Niv.
+
+let
+
+  #
+  # The fetchers. fetch_<type> fetches specs of type <type>.
+  #
+
+  fetch_file = pkgs: name: spec:
+    let
+      name' = sanitizeName name + "-src";
+    in
+    if spec.builtin or true then
+      builtins_fetchurl { inherit (spec) url sha256; name = name'; }
+    else
+      pkgs.fetchurl { inherit (spec) url sha256; name = name'; };
+
+  fetch_tarball = pkgs: name: spec:
+    let
+      name' = sanitizeName name + "-src";
+    in
+    if spec.builtin or true then
+      builtins_fetchTarball { name = name'; inherit (spec) url sha256; }
+    else
+      pkgs.fetchzip { name = name'; inherit (spec) url sha256; };
+
+  fetch_git = name: spec:
+    let
+      ref =
+        spec.ref or (
+          if spec ? branch then "refs/heads/${spec.branch}" else
+          if spec ? tag then "refs/tags/${spec.tag}" else
+          abort "In git source '${name}': Please specify `ref`, `tag` or `branch`!"
+        );
+      submodules = spec.submodules or false;
+      submoduleArg =
+        let
+          nixSupportsSubmodules = builtins.compareVersions builtins.nixVersion "2.4" >= 0;
+          emptyArgWithWarning =
+            if submodules
+            then
+              builtins.trace
+                (
+                  "The niv input \"${name}\" uses submodules "
+                  + "but your nix's (${builtins.nixVersion}) builtins.fetchGit "
+                  + "does not support them"
+                )
+                { }
+            else { };
+        in
+        if nixSupportsSubmodules
+        then { inherit submodules; }
+        else emptyArgWithWarning;
+    in
+    builtins.fetchGit
+      ({ url = spec.repo; inherit (spec) rev; inherit ref; } // submoduleArg);
+
+  fetch_local = spec: spec.path;
+
+  fetch_builtin-tarball = name: throw
+    ''[${name}] The niv type "builtin-tarball" is deprecated. You should instead use `builtin = true`.
+        $ niv modify ${name} -a type=tarball -a builtin=true'';
+
+  fetch_builtin-url = name: throw
+    ''[${name}] The niv type "builtin-url" will soon be deprecated. You should instead use `builtin = true`.
+        $ niv modify ${name} -a type=file -a builtin=true'';
+
+  #
+  # Various helpers
+  #
+
+  # https://github.com/NixOS/nixpkgs/pull/83241/files#diff-c6f540a4f3bfa4b0e8b6bafd4cd54e8bR695
+  sanitizeName = name:
+    (
+      concatMapStrings (s: if builtins.isList s then "-" else s)
+        (
+          builtins.split "[^[:alnum:]+._?=-]+"
+            ((x: builtins.elemAt (builtins.match "\\.*(.*)" x) 0) name)
+        )
+    );
+
+  # The set of packages used when specs are fetched using non-builtins.
+  mkPkgs = sources: system:
+    let
+      sourcesNixpkgs =
+        import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; }) { inherit system; };
+      hasNixpkgsPath = builtins.any (x: x.prefix == "nixpkgs") builtins.nixPath;
+      hasThisAsNixpkgsPath = <nixpkgs> == ./.;
+    in
+    if builtins.hasAttr "nixpkgs" sources
+    then sourcesNixpkgs
+    else if hasNixpkgsPath && ! hasThisAsNixpkgsPath then
+      import <nixpkgs> { }
+    else
+      abort
+        ''
+          Please specify either <nixpkgs> (through -I or NIX_PATH=nixpkgs=...) or
+          add a package called "nixpkgs" to your sources.json.
+        '';
+
+  # The actual fetching function.
+  fetch = pkgs: name: spec:
+
+    if ! builtins.hasAttr "type" spec then
+      abort "ERROR: niv spec ${name} does not have a 'type' attribute"
+    else if spec.type == "file" then fetch_file pkgs name spec
+    else if spec.type == "tarball" then fetch_tarball pkgs name spec
+    else if spec.type == "git" then fetch_git name spec
+    else if spec.type == "local" then fetch_local spec
+    else if spec.type == "builtin-tarball" then fetch_builtin-tarball name
+    else if spec.type == "builtin-url" then fetch_builtin-url name
+    else
+      abort "ERROR: niv spec ${name} has unknown type ${builtins.toJSON spec.type}";
+
+  # If the environment variable NIV_OVERRIDE_${name} is set, then use
+  # the path directly as opposed to the fetched source.
+  replace = name: drv:
+    let
+      saneName = stringAsChars (c: if (builtins.match "[a-zA-Z0-9]" c) == null then "_" else c) name;
+      ersatz = builtins.getEnv "NIV_OVERRIDE_${saneName}";
+    in
+    if ersatz == "" then drv else
+      # this turns the string into an actual Nix path (for both absolute and
+      # relative paths)
+    if builtins.substring 0 1 ersatz == "/" then /. + ersatz else /. + builtins.getEnv "PWD" + "/${ersatz}";
+
+  # Ports of functions for older nix versions
+
+  # a Nix version of mapAttrs if the built-in doesn't exist
+  mapAttrs = builtins.mapAttrs or (
+    f: set: with builtins;
+    listToAttrs (map (attr: { name = attr; value = f attr set.${attr}; }) (attrNames set))
+  );
+
+  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/lists.nix#L295
+  range = first: last: if first > last then [ ] else builtins.genList (n: first + n) (last - first + 1);
+
+  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L257
+  stringToCharacters = s: map (p: builtins.substring p 1 s) (range 0 (builtins.stringLength s - 1));
+
+  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L269
+  stringAsChars = f: s: concatStrings (map f (stringToCharacters s));
+  concatMapStrings = f: list: concatStrings (map f list);
+  concatStrings = builtins.concatStringsSep "";
+
+  # https://github.com/NixOS/nixpkgs/blob/8a9f58a375c401b96da862d969f66429def1d118/lib/attrsets.nix#L331
+  optionalAttrs = cond: as: if cond then as else { };
+
+  # fetchTarball version that is compatible between all the versions of Nix
+  builtins_fetchTarball = { url, name ? null, sha256 }@attrs:
+    let
+      inherit (builtins) lessThan nixVersion fetchTarball;
+    in
+    if lessThan nixVersion "1.12" then
+      fetchTarball ({ inherit url; } // (optionalAttrs (name != null) { inherit name; }))
+    else
+      fetchTarball attrs;
+
+  # fetchurl version that is compatible between all the versions of Nix
+  builtins_fetchurl = { url, name ? null, sha256 }@attrs:
+    let
+      inherit (builtins) lessThan nixVersion fetchurl;
+    in
+    if lessThan nixVersion "1.12" then
+      fetchurl ({ inherit url; } // (optionalAttrs (name != null) { inherit name; }))
+    else
+      fetchurl attrs;
+
+  # Create the final "sources" from the config
+  mkSources = config:
+    mapAttrs
+      (
+        name: spec:
+          if builtins.hasAttr "outPath" spec
+          then
+            abort
+              "The values in sources.json should not have an 'outPath' attribute"
+          else
+            spec // { outPath = replace name (fetch config.pkgs name spec); }
+      )
+      config.sources;
+
+  # The "config" used by the fetchers
+  mkConfig =
+    { sourcesFile ? if builtins.pathExists ./sources.json then ./sources.json else null
+    , sources ? if sourcesFile == null then { } else builtins.fromJSON (builtins.readFile sourcesFile)
+    , system ? builtins.currentSystem
+    , pkgs ? mkPkgs sources system
+    }: rec {
+      # The sources, i.e. the attribute set of spec name to spec
+      inherit sources;
+
+      # The "pkgs" (evaluated nixpkgs) to use for e.g. non-builtin fetchers
+      inherit pkgs;
+    };
+
+in
+mkSources (mkConfig { }) // { __functor = _: settings: mkSources (mkConfig settings); }
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 7829dbe..abf84ca 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1 +1,4 @@
 webtest>=2.0.16
+pytest
+InMemoryCloudDatastoreStub
+time-machine>=2.8
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..a7f2e5b
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,5 @@
+appengine-python-standard>=1.0.0
+Flask>=2.2.2
+Jinja2>=3.1.2
+google-cloud-ndb>=1.11.1
+google-cloud-logging>=3.2.5
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..7a670c1
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,105 @@
+{ sources ? import ./nix/sources.nix }:
+
+let
+  pkgs = import sources.nixpkgs {};
+
+  python = pkgs.python310.override {
+    packageOverrides = self: super: {
+
+      google-cloud-datastore-stub = super.buildPythonPackage rec {
+        pname = "InMemoryCloudDatastoreStub";
+        version = "0.0.15";
+        src = super.fetchPypi {
+          inherit pname version;
+          sha256 = "sha256-nuJNhnlXSbAg6CdWW8u7rGDDd07FvLNRtsTfzUBh7bE=";
+        };
+        propagatedBuildInputs = [
+          self.google-cloud-ndb
+        ];
+        buildInputs = [
+          super.pytest
+        ];
+      };
+
+      google-cloud-ndb = super.buildPythonPackage rec {
+        pname = "google-cloud-ndb";
+        version = "1.11.1";
+
+        src = super.fetchPypi {
+          inherit pname version;
+          sha256 = "sha256-ooEt7uTNEumYeN5EbmpVSqNKj/60OCVM4HHiUT7FaYY=";
+        };
+        propagatedBuildInputs = [
+          super.setuptools
+          super.google-cloud-core
+          self.google-cloud-datastore
+          super.pymemcache
+          super.redis
+          super.pytz
+          self.protobuf
+        ];
+        doCheck = false;
+      };
+
+      google-cloud-datastore = super.buildPythonPackage rec {
+        pname = "google-cloud-datastore";
+        version = "1.15.5";
+        src = super.fetchPypi {
+          inherit pname version;
+          sha256 = "sha256-2tyhYxCIt6c38xHfh1dKQX8lTOcdapgIDzbzW9yWsw8=";
+        };
+        propagatedBuildInputs = [
+          self.protobuf
+          super.google-cloud-core
+        ];
+        doCheck = false;
+      };
+
+      protobuf = super.protobuf.override { protobuf = pkgs.protobuf3_20; };
+
+      appengine-python-standard = super.buildPythonPackage rec {
+        pname = "appengine-python-standard";
+        version = "1.0.0";
+        src = super.fetchPypi {
+          inherit pname version;
+          sha256 = "sha256-h/HLQC6Ez4oaFkW2Kkkwb0e+QSmUQVC0wrJD4igkkrk=";
+        };
+        propagatedBuildInputs = [
+          super.requests
+          self.protobuf
+          super.attrs
+          super.google-auth
+          super.pillow
+          super.pytz
+          super.frozendict
+          super.ruamel-yaml
+          super.mock
+        ];
+      };
+    };
+
+  };
+
+  pythonEnv = python.withPackages (ps: [
+    ps.google-cloud-logging
+    ps.google-cloud-ndb
+    ps.appengine-python-standard
+    ps.flask
+    ps.pytest
+    ps.google-cloud-datastore-stub
+    ps.time-machine
+  ]);
+
+
+in pkgs.mkShell {
+  buildInputs = with pkgs; [
+    nodePackages.pyright  # Type checker
+    honcho  # Procfile runner
+    pythonEnv
+    (google-cloud-sdk.withExtraComponents ([
+      google-cloud-sdk.components.app-engine-python
+      google-cloud-sdk.components.app-engine-python-extras
+     ]))
+    jre  # gcloud datastore emulator needs jre
+  ];
+}
diff --git a/slacklib.py b/slacklib.py
index 10a4b4d..eaaf6a0 100644
--- a/slacklib.py
+++ b/slacklib.py
@@ -1,6 +1,4 @@
 # -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
 """Snippets server -> Slack integration.
 
 This provides Slack integration with the snippet server, for
@@ -21,14 +19,12 @@
 import json
 import logging
 import re
-import os
 import textwrap
-import urllib
-import urllib2
-import webapp2
+import urllib.error
+import urllib.parse
+import urllib.request
 
-from google.appengine.ext import db
-from google.appengine.api import memcache
+import flask
 
 import models
 import util
@@ -40,11 +36,7 @@
 _REQUIRE_SLASH_TOKEN = True
 
 
-# This allows mocking in a different day, for testing.
-_TODAY_FN = datetime.datetime.now
-
-# The web URL we point people to as the base for web operations
-_WEB_URL = 'http://' + os.environ.get('SERVER_NAME', 'localhost')
+app_blueprint = flask.Blueprint("slack", __name__, url_prefix="/slack")
 
 
 def _web_api(api_method, payload):
@@ -59,7 +51,8 @@ def _web_api(api_method, payload):
     app_settings = models.AppSettings.get()
     payload.setdefault('token', app_settings.slack_token)
     uri = 'https://slack.com/api/' + api_method
-    r = urllib2.urlopen(uri, urllib.urlencode(payload))
+    r = urllib.request.urlopen(uri,
+                               urllib.parse.urlencode(payload).encode('utf-8'))
 
     # check return code for server errors
     if r.getcode() != 200:
@@ -72,40 +65,6 @@ def _web_api(api_method, payload):
     return reply
 
 
-def _get_user_email(uid):
-    """Retrieve the email address for a specific userid from the Slack Web API.
-
-    Raises ValueError if could not be retrieved.
-    """
-    reply = _web_api('users.info', {'user': uid})  # possible ValueError
-    email = reply.get('user', {}).get('profile', {}).get('email', None)
-    if email is None:
-        raise ValueError('Slack user profile did not have email')
-    return email
-
-
-def _get_user_email_cached(uid, force_refresh=False):
-    """Retrieve the email address for a specific user id, with a cache.
-
-    Results are stored in memcache for up to a day.
-
-    If force_refresh parameter is specified, cached data will be refreshed.
-
-    Raises ValueError if could not be retrieved.
-    """
-    key = 'slack_profile_email_' + uid
-    cached_data = memcache.get(key)
-    if (cached_data is None) or force_refresh:
-        logging.debug("cache miss/refresh for slack email lookup %s", uid)
-        email = _get_user_email(uid)  # possible ValueError
-        if not memcache.set(key=key, value=email, time=86400):
-            logging.error('memcache set failed!')
-        return email
-    else:
-        logging.debug("cache hit for slack email lookup %s", uid)
-        return cached_data
-
-
 def send_to_slack_channel(channel, msg):
     """Send a plaintext message to a Slack channel."""
     try:
@@ -116,7 +75,7 @@ def send_to_slack_channel(channel, msg):
             'icon_emoji': ':pencil:',
             'unfurl_links': False,    # no link previews, please
         })
-    except ValueError, why:
+    except ValueError as why:
         logging.error('Failed sending message to slack: %s', why)
 
 
@@ -138,20 +97,25 @@ def command_usage():
 
 def command_help():
     """Return the help string for slash commands."""
+    app_settings = models.AppSettings.get()
     return (
         "I can help you manage your "
-        "<{}|weekly snippets>! :pencil:".format(_WEB_URL) +
+        "<{}|weekly snippets>! :pencil:".format(app_settings.hostname) +
         command_usage()
     )
 
 
-def _no_user_error(user_email):
-    return (
-        "You don't appear to have a snippets account yet!\n"
-        "To create one, go to {}\n"
-        "We looked for your Slack email address: {}"
-        .format(_WEB_URL, user_email)
-    )
+def _no_user_error(user_id):
+    try:
+        app_settings = models.AppSettings.get()
+        return (f"You don't seem to be logged in!  Please configure your slack "
+                f"user ID (which is `{user_id}`) in the snippets server's "
+                f"settings page: {app_settings.hostname}/settings")
+    except ValueError:
+        return (
+            "You don't seem to be logged in, and this snippets server is "
+            "unconfigured!  Please ask your snippets admin to set it up "
+            "before trying again.")
 
 
 def _user_snippet(user_email, weeks_back=0):
@@ -175,7 +139,8 @@ def _user_snippet(user_email, weeks_back=0):
     )
 
     filled_snips = util.fill_in_missing_snippets(user_snips, account,
-                                                 user_email, _TODAY_FN())
+                                                 user_email,
+                                                 datetime.datetime.now())
     logging.debug(
         'User %s snippets *filled* to: %s', user_email, len(filled_snips)
     )
@@ -217,7 +182,7 @@ def _format_snippet_items(items):
     return "\n".join(fi)
 
 
-def command_list(user_email):
+def command_list(user_email: str) -> str:
     """Return the users current snippets for the week in pretty format."""
     try:
         items = _snippet_items(_user_snippet(user_email))
@@ -305,12 +270,11 @@ def command_add(user_email, new_item):
     snippet.is_markdown = True
 
     # TODO(mroth): we should abstract out DB writes to a library wrapper
-    db.put(snippet)
-    db.get(snippet.key())    # ensure db consistency for HRD
+    snippet.put()
     return "Added *{}* to your weekly snippets.".format(new_item)
 
 
-def command_del(user_email, args):
+def command_del(user_email, args) -> str:
     """Delete an item at an index from the users current snippets.
 
     The `args` parameter should be the args passed to the command.  We
@@ -354,8 +318,7 @@ def command_del(user_email, args):
     snippet.text = _markdown_list(items)
     snippet.is_markdown = True
 
-    db.put(snippet)
-    db.get(snippet.key())    # ensure db consistency for HRD
+    snippet.put()
     return "Removed *{}* from your weekly snippets.".format(removed_item)
 
 
@@ -368,95 +331,85 @@ def command_dump(user_email):
     return "```{}```".format(snippet.text or 'No snippet yet for this week')
 
 
-class SlashCommand(webapp2.RequestHandler):
-    def post(self):
-        """Process an incoming slash command from Slack.
-
-        Incoming request POST looks like the following (example taken from
-        https://api.slack.com/slash-commands):
-            token=gIkuvaNzQIHg97ATvDxqgjtO
-            team_id=T0001
-            team_domain=example
-            channel_id=C2147483705
-            channel_name=test
-            user_id=U2147483697
-            user_name=Steve
-            command=/weather
-            text=94070
-        """
-        req, res = self.request, self.response
-
-        expected_token = models.AppSettings.get().slack_slash_token
-
-        if not expected_token:
-            res.write('Slack slash commands disabled. An admin '
-                      'can enable them at /admin/settings')
-            return
-
-        # verify slash API post token for security
-        if _REQUIRE_SLASH_TOKEN:
-            token = req.get('token')
-            if token != expected_token:
-                logging.error("POST MADE WITH INVALID TOKEN")
-                res.write("OH NO YOU DIDNT! Security issue plz contact admin.")
-                return
-
-        user_name = req.get('user_name')
-        user_id = req.get('user_id')
-        text = req.get('text')
-
-        try:
-            user_email = _get_user_email_cached(user_id)
-        except ValueError:
-            logging.error("Failed getting %s email from Slack API", user_name)
-            res.write(
-                "Error getting your email address from the Slack API! "
-                "Please contact an admin and report the time of this error."
-            )
-            return
+def get_user_by_slack_id(slack_id: str) -> models.User:
+    return models.User.query(models.User.slack_id == slack_id).get()
+
 
-        words = text.strip().split()
-        if not words:
-            logging.info('null (list) command from user %s', user_name)
-            res.write(command_list(user_email))
+# This route is actually /slack because app_blueprint sets url_prefix
+@app_blueprint.route("/", methods=["POST"])
+def slash_command_handler() -> str:
+    """Process an incoming slash command from Slack.
+
+    Incoming request POST looks like the following (example taken from
+    https://api.slack.com/slash-commands):
+        token=gIkuvaNzQIHg97ATvDxqgjtO
+        team_id=T0001
+        team_domain=example
+        channel_id=C2147483705
+        channel_name=test
+        user_id=U2147483697
+        user_name=Steve
+        command=/weather
+        text=94070
+    """
+    req = flask.request
+
+    app_settings = models.AppSettings.get()
+    expected_token = app_settings.slack_slash_token
+
+    if not expected_token:
+        return ('Slack slash commands disabled. An admin '
+                'can enable them at /admin/settings')
+
+    # verify slash API post token for security
+    if _REQUIRE_SLASH_TOKEN:
+        token = req.form.get('token')
+        if token != expected_token:
+            logging.error("POST MADE WITH INVALID TOKEN")
+            return "OH NO YOU DIDNT! Security issue plz contact admin."
+
+    user_name = req.form.get('user_name')
+    user_id = req.form.get('user_id')
+    text = req.form.get('text')
+
+    user = get_user_by_slack_id(user_id)
+    if user is None:
+        logging.info("Slack command from unrecognized user_id: %s", user_id)
+        return _no_user_error(user_id)
+
+    words = text.strip().split()
+    if not words:
+        logging.info('null (list) command from user %s', user_name)
+        return command_list(user.email)
+    else:
+        cmd, args = words[0], words[1:]
+        if cmd == 'help':
+            logging.info('help command from user %s', user_name)
+            return command_help()
+        elif cmd == 'whoami':
+            # undocumented command to echo user email back
+            logging.info('whoami command from user %s', user_name)
+            return str(user.email)
+        elif cmd == 'list':
+            # this is the same as the null command, but support for UX
+            logging.info('list command from user %s', user_name)
+            return command_list(user.email)
+        elif cmd == 'last':
+            logging.info('last command from user %s', user_name)
+            return command_last(user.email)
+        elif cmd == 'add':
+            logging.info('add command from user %s', user_name)
+            return command_add(user.email, " ".join(args))
+        elif cmd == 'del':
+            logging.info('del command from user %s', user_name)
+            return command_del(user.email, args)
+        elif cmd == 'dump':
+            logging.info('dump command from user %s', user_name)
+            return command_dump(user.email)
         else:
-            cmd, args = words[0], words[1:]
-            if cmd == 'help':
-                logging.info('help command from user %s', user_name)
-                res.write(command_help())
-            elif cmd == 'whoami':
-                # undocumented command to echo user email back
-                logging.info('whoami command from user %s', user_name)
-                res.write(user_email)
-            elif cmd == 'whoami!':
-                # whoami! forces a refresh of cache, for debugging
-                logging.info('whoami! command from user %s', user_name)
-                logging.info('whoami! potential cached email for %s: %s',
-                             user_name, user_email)
-                refreshed = _get_user_email_cached(user_id, force_refresh=True)
-                logging.info('whoami! refreshed email for %s: %s',
-                             user_name, refreshed)
-                res.write(refreshed)
-            elif cmd == 'list':
-                # this is the same as the null command, but support for UX
-                logging.info('list command from user %s', user_name)
-                res.write(command_list(user_email))
-            elif cmd == 'last':
-                logging.info('last command from user %s', user_name)
-                res.write(command_last(user_email))
-            elif cmd == 'add':
-                logging.info('add command from user %s', user_name)
-                res.write(command_add(user_email, " ".join(args)))
-            elif cmd == 'del':
-                logging.info('del command from user %s', user_name)
-                res.write(command_del(user_email, args))
-            elif cmd == 'dump':
-                logging.info('dump command from user %s', user_name)
-                res.write(command_dump(user_email))
-            else:
-                logging.info('unknown command %s from user %s', cmd, user_name)
-                res.write(
-                    "I don't understand what you said! "
-                    "Perhaps you meant one of these?\n```%s```\n"
-                    % command_usage()
-                )
+            logging.info('unknown command %s from user %s', cmd, user_name)
+            return (
+                "I don't understand what you said! "
+                "Perhaps you meant one of these?\n```%s```\n"
+                % command_usage()
+            )
diff --git a/slacklib_test.py b/slacklib_test.py
index 11cc2c7..5bc2905 100644
--- a/slacklib_test.py
+++ b/slacklib_test.py
@@ -1,39 +1,45 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
-from __future__ import unicode_literals
 
 import datetime
 import textwrap
 import unittest
+from zoneinfo import ZoneInfo
 
-# Update sys.path so it can find these.  We just need to add
-# 'google_appengine', but we add all of $PATH to be easy.  This
-# assumes the google_appengine directory is on the path.
-import os
-import sys
-sys.path.extend(os.environ['PATH'].split(':'))
-import dev_appserver
-dev_appserver.fix_sys_path()
-from google.appengine.ext import db
 from google.appengine.ext import testbed
+import time_machine
 
 import models
 import slacklib
 
-
+# The fictional date for these tests is Wednesday, July 29, 2015
+@time_machine.travel(datetime.datetime(2015, 7, 29, tzinfo=ZoneInfo("UTC")))
 class SlashCommandTest(unittest.TestCase):
 
-    def _mock_data(self):
-        # The fictional day for these tests Wednesday, July 29, 2015
-        slacklib._TODAY_FN = lambda: datetime.datetime(2015, 7, 29)
+    def setUp(self):
+        self.testbed = testbed.Testbed()
+        self.testbed.activate()
+        self.testbed.init_user_stub()
+
+        self.testbed.setup_env(
+            user_email="bob@example.com",
+            user_id="bob@example.com",
+            user_is_admin='0',
+            overwrite=True
+        )
+        appsettings = models.AppSettings.get(
+            create_if_missing=True,
+            domains=["khanacademy.org"],
+        )
+        appsettings.put()
 
         # Stuart created his account, but has never once filled out a snippet
-        db.put(models.User(email='stuart@khanacademy.org'))
+        models.User(email='stuart@khanacademy.org').put()
 
         # Fleetwood has two recent snippets, and always uses markdown lists,
         # but sometimes uses different list indicators or indention.
-        db.put(models.User(email='fleetwood@khanacademy.org'))
-        db.put(models.Snippet(
+        models.User(email='fleetwood@khanacademy.org').put()
+        models.Snippet(
             email='fleetwood@khanacademy.org',
             week=datetime.date(2015, 7, 27),
             text=textwrap.dedent("""
@@ -41,21 +47,21 @@ def _mock_data(self):
             *  sniffed some things
             *  hoping to sniff more things! #yolo
             """)
-        ))
-        db.put(models.Snippet(
+        ).put()
+        models.Snippet(
             email='fleetwood@khanacademy.org',
             week=datetime.date(2015, 7, 20),
             text=textwrap.dedent("""
             - lots of walks this week
             - not enough sniffing, hope to remedy next week!
             """)
-        ))
+        ).put()
 
         # Toby has filled out two snippets, but missed a week in-between while
         # on vacation. When he got back from vacation he was still jetlagged so
         # he wrote a longform paragraph instead of a list.
-        db.put(models.User(email='toby@khanacademy.org'))
-        db.put(models.Snippet(
+        models.User(email='toby@khanacademy.org').put()
+        models.Snippet(
             email='toby@khanacademy.org',
             week=datetime.date(2015, 7, 13),
             text=textwrap.dedent("""
@@ -63,8 +69,8 @@ def _mock_data(self):
 
 
             """)
-        ))
-        db.put(models.Snippet(
+        ).put()
+        models.Snippet(
             email='toby@khanacademy.org',
             week=datetime.date(2015, 7, 27),
             text=textwrap.dedent("""
@@ -76,37 +82,30 @@ def _mock_data(self):
 
             LUNCHTIME SUCKERS!
             """)
-        ))
+        ).put()
 
         # Fozzie tried hard to create an entry manually in the previous week,
         # but didn't understand markdown list syntax and got discouraged (so
         # has no entry this week, and a malformed one last week).
-        db.put(models.User(email='fozzie@khanacademy.org'))
-        db.put(models.Snippet(
+        models.User(email='fozzie@khanacademy.org').put()
+        models.Snippet(
             email='fozzie@khanacademy.org',
             week=datetime.date(2015, 7, 20),
             text=textwrap.dedent("""
             -is this how I list?
             -why is it not formatting??!?
             """)
-        ))
-
-    def _most_recent_snippet(self, user_email):
-        snippets_q = models.Snippet.all()
-        snippets_q.filter('email = ', user_email)
-        snippets_q.order('-week')        # newest snippet first
-        return snippets_q.fetch(1)[0]
-
-    def setUp(self):
-        self.testbed = testbed.Testbed()
-        self.testbed.activate()
-        self.testbed.init_datastore_v3_stub()
-        self.testbed.init_memcache_stub()
-        self._mock_data()
+        ).put()
 
     def tearDown(self):
         self.testbed.deactivate()
 
+    def _most_recent_snippet(self, user_email):
+        snippets_q = models.Snippet.query(
+            models.Snippet.email == user_email
+        ).order('-week')  # newest snippet first
+        return snippets_q.fetch(1)[0]
+
     def testDumpCommand_empty(self):
         # user without a recent snippet should just see null text
         response = slacklib.command_dump('stuart@khanacademy.org')
@@ -120,8 +119,8 @@ def testDumpCommand_formatting(self):
     def testDumpCommand_noAccount(self):
         # user without an account should get a helpful error message
         response = slacklib.command_dump('bob@bob.com')
-        self.assertIn("You don't appear to have a snippets account", response)
-        self.assertIn("Slack email address: bob@bob.com", response)
+        self.assertIn("You don't seem to be logged in!", response)
+        self.assertIn("bob@bob.com", response)
 
     def testListCommand_empty(self):
         # user without a recent snippet should get a helpful message
@@ -142,7 +141,7 @@ def testListCommand_formatting(self):
     def testListCommand_noAccount(self):
         # user without an account should get a helpful error message
         response = slacklib.command_list('bob@bob.com')
-        self.assertIn("You don't appear to have a snippets account", response)
+        self.assertIn("You don't seem to be logged in!", response)
 
     def testLastCommand_empty(self):
         # user without a snippet last week should get a helpful message
@@ -160,7 +159,7 @@ def testLastCommand_formatting(self):
     def testLastCommand_noAccount(self):
         # user without an account should get a helpful error message
         response = slacklib.command_last('bob@bob.com')
-        self.assertIn("You don't appear to have a snippets account", response)
+        self.assertIn("You don't seem to be logged in!", response)
 
     def testBadMarkdown_listCommand(self):
         toby_recent = slacklib.command_list('toby@khanacademy.org')
@@ -175,8 +174,8 @@ def testAddCommand_blank(self):
         r = slacklib.command_add('stuart@khanacademy.org', 'went to the park')
         t = self._most_recent_snippet('stuart@khanacademy.org')
         self.assertIn("Added *went to the park* to your weekly snippets", r)
-        self.assertEquals('- went to the park', t.text)
-        self.assertEquals(True, t.is_markdown)
+        self.assertEqual('- went to the park', t.text)
+        self.assertEqual(True, t.is_markdown)
 
     def testAddCommand_existing(self):
         # on this one, the user markdown formatting gets altered/standardized
@@ -189,7 +188,7 @@ def testAddCommand_existing(self):
             - went to the park
         """).strip()
         self.assertEqual(expected, t.text)
-        self.assertEquals(True, t.is_markdown)
+        self.assertEqual(True, t.is_markdown)
 
     def testAddCommand_existingIsMalformed(self):
         # we should be told we cannot to add to a snippet that is malformed!
@@ -200,7 +199,7 @@ def testAddCommand_existingIsMalformed(self):
         t = self._most_recent_snippet(toby_email)
         self.assertNotIn("went to the park", t.text)
         self.assertIn("LUNCHTIME SUCKERS!", t.text)
-        self.assertEquals(False, t.is_markdown)
+        self.assertEqual(False, t.is_markdown)
 
     def testAddCommand_noArgs(self):
         # we need to handle when they try to add nothing!
@@ -210,7 +209,7 @@ def testAddCommand_noArgs(self):
     def testAddCommand_noAccount(self):
         # dont crash horribly if user doesnt exist
         r = slacklib.command_add('bob@bob.com', 'how is account formed?')
-        self.assertIn("You don't appear to have a snippets account", r)
+        self.assertIn("You don't seem to be logged in!", r)
 
     def testAddCommand_markupUsernames(self):
         # usernames should be marked up properly so they get syntax highlighted
@@ -220,7 +219,7 @@ def testAddCommand_markupUsernames(self):
         self.assertIn("- ate w/ <@toby>, yay", t.text)
 
     def testAddCommand_unicode(self):
-        r = slacklib.command_add('stuart@khanacademy.org', u'i “like” food')
+        r = slacklib.command_add('stuart@khanacademy.org', 'i “like” food')
         t = self._most_recent_snippet('stuart@khanacademy.org')
         self.assertIn('i “like” food', r)
         self.assertIn('i “like” food', t.text)
@@ -233,7 +232,7 @@ def testDelCommand_noArgs(self):
     def testDelCommand_noAccount(self):
         # dont crash horribly if user doesnt exist
         r = slacklib.command_del('bob@bob.com', ['1'])
-        self.assertIn("You don't appear to have a snippets account", r)
+        self.assertIn("You don't seem to be logged in!", r)
 
     def testDelCommand_normalCase(self):
         r = slacklib.command_del('fleetwood@khanacademy.org', ['1'])
@@ -245,7 +244,7 @@ def testDelCommand_normalCase(self):
             - hoping to sniff more things! #yolo
         """).strip()
         self.assertEqual(expected, t.text)
-        self.assertEquals(True, t.is_markdown)
+        self.assertEqual(True, t.is_markdown)
 
     def testDelCommand_nonexistentIndex(self):
         r1 = slacklib.command_del('stuart@khanacademy.org', ['0'])
@@ -265,7 +264,4 @@ def testDelCommand_existingIsMalformed(self):
         # ...and the existing snippets should not have been touched
         t = self._most_recent_snippet('toby@khanacademy.org')
         self.assertIn("I had fun", t.text)
-        self.assertEquals(False, t.is_markdown)
-
-if __name__ == '__main__':
-    unittest.main()
+        self.assertEqual(False, t.is_markdown)
diff --git a/snippets.py b/snippets.py
index 9d6f286..8d49679 100644
--- a/snippets.py
+++ b/snippets.py
@@ -13,38 +13,47 @@
 import os
 import re
 import time
-import urllib
+import urllib.parse
 
 from google.appengine.api import mail
 from google.appengine.api import users
-from google.appengine.ext import db
-import webapp2
-from webapp2_extras import jinja2
+from google.cloud import ndb
+import google.cloud.logging
+import flask
 
 import models
 import slacklib
 import util
 
+if os.getenv("GAE_ENV", "").startswith("standard"):
+    # We're running in the real appengine environment, hopefully.
+    # Set up cloud logging
+    logging_client = google.cloud.logging.Client()
+    logging_client.setup_logging(log_level=logging.INFO)
 
-# This allows mocking in a different day, for testing.
-_TODAY_FN = datetime.datetime.now
+app = flask.Flask(
+    __name__,
+    # Drop /static prefix for things like /favicon.ico
+    static_url_path="",
+    static_folder="static",
+    template_folder="templates")
 
+app.register_blueprint(slacklib.app_blueprint)
 
-jinja2.default_config['template_path'] = os.path.join(
-    os.path.dirname(__file__),
-    "templates"
-)
-jinja2.default_config['filters'] = {
-    'readable_date': (
-        lambda value: value.strftime('%B %d, %Y').replace(' 0', ' ')),
-    'iso_date': (
-        lambda value: value.strftime('%m-%d-%Y')),
-}
 
+@app.template_filter("readable_date")
+def _readable_date_filter(value: datetime.date):
+    return value.strftime('%B %d, %Y').replace(' 0', ' ')
 
-def _login_page(request, redirector):
+
+@app.template_filter("iso_date")
+def _iso_date_filter(value: datetime.date):
+    return value.strftime("%m-%d-%Y")
+
+
+def _login_page(request):
     """Redirect the user to a page where they can log in."""
-    redirector.redirect(users.create_login_url(request.uri))
+    return flask.redirect(users.create_login_url(request.url))
 
 
 def _current_user_email():
@@ -70,19 +79,21 @@ def _get_or_create_user(email, put_new_user=True):
             # TODO(csilvers): move this get/update/put atomic into a txn
             user.is_hidden = False
             user.put()
+        return user
     elif not _logged_in_user_has_permission_for(email):
         # TODO(csilvers): turn this into a 403 somewhere
         raise IndexError('User "%s" not found; did you specify'
                          ' the full email address?' % email)
     else:
-        # You can only create a new user under one of the app-listed domains.
         try:
             app_settings = models.AppSettings.get()
         except ValueError:
             # TODO(csilvers): do this instead:
             #                 /admin/settings?redirect_to=user_setting
-            return None
+            # return None
+            raise  # TODO(benley) implement Redirect exception
 
+        # You can only create a new user under one of the app-listed domains.
         domain = email.split('@')[-1]
         allowed_domains = app_settings.domains
         if domain not in allowed_domains:
@@ -93,15 +104,14 @@ def _get_or_create_user(email, put_new_user=True):
                                % (' or '.join(allowed_domains), domain))
 
         # Set the user defaults based on the global app defaults.
-        user = models.User(created=_TODAY_FN(),
+        user = models.User(created=datetime.datetime.now(),
                            email=email,
                            uses_markdown=app_settings.default_markdown,
                            private_snippets=app_settings.default_private,
                            wants_email=app_settings.default_email)
         if put_new_user:
-            db.put(user)
-            db.get(user.key())    # ensure db consistency for HRD
-    return user
+            user.put()
+        return user
 
 
 def _logged_in_user_has_permission_for(email):
@@ -146,527 +156,530 @@ def _send_to_chat(msg, url_path):
         slacklib.send_to_slack_channel(slack_channel, msg)
 
 
-class BaseHandler(webapp2.RequestHandler):
-    """Set up as per the jinja2.py docstring."""
-    @webapp2.cached_property
-    def jinja2(self):
-        return jinja2.get_jinja2()
+@app.route("/")
+def user_page_handler():
+    """Show all the snippets for a single user."""
 
-    def render_response(self, template_filename, context):
-        html = self.jinja2.render_template(template_filename, **context)
-        self.response.write(html)
+    if not users.get_current_user():
+        return _login_page(flask.request)
 
+    user_email = flask.request.args.get('u', _current_user_email())
+    user = util.get_user(user_email)
 
-class UserPage(BaseHandler):
-    """Show all the snippets for a single user."""
+    now = datetime.datetime.now()
 
-    def get(self):
-        if not users.get_current_user():
-            return _login_page(self.request, self)
-
-        user_email = self.request.get('u', _current_user_email())
-        user = util.get_user(user_email)
-
-        if not user:
-            # If there are no app settings, set those up before setting
-            # up the user settings.
-            if users.is_current_user_admin():
-                try:
-                    models.AppSettings.get()
-                except ValueError:
-                    self.redirect("/admin/settings?redirect_to=user_setting"
-                                  "&msg=Welcome+to+the+snippet+server!+"
-                                  "Please+take+a+moment+to+configure+it.")
-                    return
-
-            template_values = {
-                'new_user': True,
-                'login_url': users.create_login_url(self.request.uri),
-                'logout_url': users.create_logout_url('/'),
-                'username': user_email,
-            }
-            self.render_response('new_user.html', template_values)
-            return
-
-        snippets = util.snippets_for_user(user_email)
-
-        if not _can_view_private_snippets(_current_user_email(), user_email):
-            snippets = [snippet for snippet in snippets if not snippet.private]
-        snippets = util.fill_in_missing_snippets(snippets, user,
-                                                 user_email, _TODAY_FN())
-        snippets.reverse()                  # get to newest snippet first
+    if not user:
+        # If there are no app settings, set those up before setting
+        # up the user settings.
+        if users.is_current_user_admin():
+            try:
+                models.AppSettings.get()
+            except ValueError:
+                return flask.redirect(
+                    "/admin/settings?redirect_to=user_setting"
+                    "&msg=Welcome+to+the+snippet+server!+"
+                    "Please+take+a+moment+to+configure+it.")
 
         template_values = {
+            'new_user': True,
+            'login_url': users.create_login_url(flask.request.url),
             'logout_url': users.create_logout_url('/'),
-            'message': self.request.get('msg'),
             'username': user_email,
-            'is_admin': users.is_current_user_admin(),
-            'domain': user_email.split('@')[-1],
-            'view_week': util.existingsnippet_monday(_TODAY_FN()),
-            # Snippets for the week of <one week ago> are due today.
-            'one_week_ago': _TODAY_FN().date() - datetime.timedelta(days=7),
-            'eight_days_ago': _TODAY_FN().date() - datetime.timedelta(days=8),
-            'editable': (_logged_in_user_has_permission_for(user_email) and
-                         self.request.get('edit', '1') == '1'),
-            'user': user,
-            'snippets': snippets,
-            'null_category': models.NULL_CATEGORY,
         }
-        self.render_response('user_snippets.html', template_values)
+        return flask.render_template('new_user.html', **template_values)
+
+    snippets = util.snippets_for_user(user_email)
+
+    if not _can_view_private_snippets(_current_user_email(), user_email):
+        snippets = [snippet for snippet in snippets if not snippet.private]
+    snippets = util.fill_in_missing_snippets(snippets, user, user_email, now)
+    snippets.reverse()  # get to newest snippet first
+
+    template_values = {
+        'logout_url': users.create_logout_url('/'),
+        'message': flask.request.args.get('msg'),
+        'username': user_email,
+        'is_admin': users.is_current_user_admin(),
+        'domain': user_email.split('@')[-1],
+        'view_week': util.existingsnippet_monday(now),
+        # Snippets for the week of <one week ago> are due today.
+        'one_week_ago': now.date() - datetime.timedelta(days=7),
+        'eight_days_ago': now.date() - datetime.timedelta(days=8),
+        'editable': (_logged_in_user_has_permission_for(user_email) and
+                     flask.request.args.get('edit', '1') == '1'),
+        'user': user,
+        'snippets': snippets,
+        'null_category': models.NULL_CATEGORY,
+    }
+    return flask.render_template('user_snippets.html', **template_values)
 
 
 def _title_case(s):
     """Like string.title(), but does not uppercase 'and'."""
-    # Smarter would be to use 'pip install titlecase'.
-    SMALL = 'a|an|and|as|at|but|by|en|for|if|in|of|on|or|the|to|v\.?|via|vs\.?'
+    # TODO(benley): use titlecase from pypi?
+    SMALL = r'a|an|and|as|at|but|by|en|for|if|in|of|on|or|the|to|v\.?|via|vs\.?'
     # We purposefully don't match small words at the beginning of a string.
     SMALL_RE = re.compile(r' (%s)\b' % SMALL, re.I)
     return SMALL_RE.sub(lambda m: ' ' + m.group(1).lower(), s.title().strip())
 
 
-class SummaryPage(BaseHandler):
+@app.route("/weekly")
+def summary_page_handler():
     """Show all the snippets for a single week."""
 
-    def get(self):
-        if not users.get_current_user():
-            return _login_page(self.request, self)
+    if not users.get_current_user():
+        return _login_page(flask.request)
 
-        week_string = self.request.get('week')
-        if week_string:
-            week = datetime.datetime.strptime(week_string, '%m-%d-%Y').date()
+    week_string = flask.request.args.get('week')
+    if week_string:
+        week = datetime.datetime.strptime(week_string, '%m-%d-%Y').date()
+    else:
+        week = util.existingsnippet_monday(datetime.datetime.now())
+
+    snippets_q = models.Snippet.query(
+        models.Snippet.week == week
+    )
+    snippets = snippets_q.fetch(1000)   # good for many users...
+    # TODO(csilvers): filter based on wants_to_view
+
+    # Get all the user records so we can categorize snippets.
+    user_q = models.User.query()
+    results = user_q.fetch(1000)
+    email_to_category = {}
+    email_to_user = {}
+    for result in results:
+        # People aren't very good about capitalizing their
+        # categories consistently, so we enforce title-case,
+        # with exceptions for 'and'.
+        email_to_category[result.email] = _title_case(result.category)
+        email_to_user[result.email] = result
+
+    # Collect the snippets and users by category.  As we see each email,
+    # delete it from email_to_category.  At the end of this,
+    # email_to_category will hold people who did not give
+    # snippets this week.
+    snippets_and_users_by_category = {}
+    for snippet in snippets:
+        # Ignore this snippet if we don't have permission to view it.
+        if (snippet.private and
+                not _can_view_private_snippets(_current_user_email(),
+                                                snippet.email)):
+            continue
+        category = email_to_category.get(
+            snippet.email, models.NULL_CATEGORY
+        )
+        if snippet.email in email_to_user:
+            snippets_and_users_by_category.setdefault(category, []).append(
+                (snippet, email_to_user[snippet.email])
+            )
         else:
-            week = util.existingsnippet_monday(_TODAY_FN())
-
-        snippets_q = models.Snippet.all()
-        snippets_q.filter('week = ', week)
-        snippets = snippets_q.fetch(1000)   # good for many users...
-        # TODO(csilvers): filter based on wants_to_view
-
-        # Get all the user records so we can categorize snippets.
-        user_q = models.User.all()
-        results = user_q.fetch(1000)
-        email_to_category = {}
-        email_to_user = {}
-        for result in results:
-            # People aren't very good about capitalizing their
-            # categories consistently, so we enforce title-case,
-            # with exceptions for 'and'.
-            email_to_category[result.email] = _title_case(result.category)
-            email_to_user[result.email] = result
-
-        # Collect the snippets and users by category.  As we see each email,
-        # delete it from email_to_category.  At the end of this,
-        # email_to_category will hold people who did not give
-        # snippets this week.
-        snippets_and_users_by_category = {}
-        for snippet in snippets:
-            # Ignore this snippet if we don't have permission to view it.
-            if (snippet.private and
-                    not _can_view_private_snippets(_current_user_email(),
-                                                   snippet.email)):
-                continue
-            category = email_to_category.get(
-                snippet.email, models.NULL_CATEGORY
+            snippets_and_users_by_category.setdefault(category, []).append(
+                (snippet, models.User(email=snippet.email))
             )
-            if snippet.email in email_to_user:
-                snippets_and_users_by_category.setdefault(category, []).append(
-                    (snippet, email_to_user[snippet.email])
-                )
-            else:
-                snippets_and_users_by_category.setdefault(category, []).append(
-                    (snippet, models.User(email=snippet.email))
-                )
-
-            if snippet.email in email_to_category:
-                del email_to_category[snippet.email]
-
-        # Add in empty snippets for the people who didn't have any --
-        # unless a user is marked 'hidden'.  (That's what 'hidden'
-        # means: pretend they don't exist until they have a non-empty
-        # snippet again.)
-        for (email, category) in email_to_category.iteritems():
-            if not email_to_user[email].is_hidden:
-                snippet = models.Snippet(email=email, week=week)
-                snippets_and_users_by_category.setdefault(category, []).append(
-                    (snippet, email_to_user[snippet.email])
-                )
-
-        # Now get a sorted list, categories in alphabetical order and
-        # each snippet-author within the category in alphabetical
-        # order.
-        # The data structure is ((category, ((snippet, user), ...)), ...)
-        categories_and_snippets = []
-        for (category,
-             snippets_and_users) in snippets_and_users_by_category.iteritems():
-            snippets_and_users.sort(key=lambda (snippet, user): snippet.email)
-            categories_and_snippets.append((category, snippets_and_users))
-        categories_and_snippets.sort()
 
-        template_values = {
-            'logout_url': users.create_logout_url('/'),
-            'message': self.request.get('msg'),
-            # Used only to switch to 'username' mode and to modify settings.
-            'username': _current_user_email(),
-            'is_admin': users.is_current_user_admin(),
-            'prev_week': week - datetime.timedelta(7),
-            'view_week': week,
-            'next_week': week + datetime.timedelta(7),
-            'categories_and_snippets': categories_and_snippets,
-        }
-        self.render_response('weekly_snippets.html', template_values)
+        if snippet.email in email_to_category:
+            del email_to_category[snippet.email]
+
+    # Add in empty snippets for the people who didn't have any --
+    # unless a user is marked 'hidden'.  (That's what 'hidden'
+    # means: pretend they don't exist until they have a non-empty
+    # snippet again.)
+    for (email, category) in email_to_category.items():
+        if not email_to_user[email].is_hidden:
+            snippet = models.Snippet(email=email, week=week)
+            snippets_and_users_by_category.setdefault(category, []).append(
+                (snippet, email_to_user[snippet.email])
+            )
+
+    # Now get a sorted list, categories in alphabetical order and
+    # each snippet-author within the category in alphabetical
+    # order.
+    # The data structure is ((category, ((snippet, user), ...)), ...)
+    categories_and_snippets = []
+    for category, snippets_and_users in snippets_and_users_by_category.items():
+        # This looks stupid but python no longer allows lambda (snippet, user): snippet.email
+        snippets_and_users.sort(key=lambda snippet_user: snippet_user[0].email)
+        categories_and_snippets.append((category, snippets_and_users))
+    categories_and_snippets.sort()
+
+    template_values = {
+        'logout_url': users.create_logout_url('/'),
+        'message': flask.request.args.get('msg'),
+        # Used only to switch to 'username' mode and to modify settings.
+        'username': _current_user_email(),
+        'is_admin': users.is_current_user_admin(),
+        'prev_week': week - datetime.timedelta(7),
+        'view_week': week,
+        'next_week': week + datetime.timedelta(7),
+        'categories_and_snippets': categories_and_snippets,
+    }
+    return flask.render_template('weekly_snippets.html', **template_values)
+
+
+def update_snippet(email: str,
+                   week: datetime.date,
+                   text: str,
+                   private: bool,
+                   is_markdown: bool):
+    assert week.weekday() == 0, 'passed-in date must be a Monday'
+
+    # TODO(csilvers): make this get-update-put atomic.
+    # (maybe make the snippet id be email + week).
+    q = models.Snippet.query(
+               models.Snippet.email == email,
+               models.Snippet.week == week
+    )
+    snippet = q.get()
+
+    # When adding a snippet, make sure we create a user record for
+    # that email as well, if it doesn't already exist.
+    user = _get_or_create_user(email)
+
+    # Store user's display_name in snippet so that if a user is later
+    # deleted, we could still show his / her display_name.
+    if snippet:
+        snippet.text = text   # just update the snippet text
+        snippet.display_name = user.display_name
+        snippet.private = private
+        snippet.is_markdown = is_markdown
+    else:
+        # add the snippet to the db
+        snippet = models.Snippet(created=datetime.datetime.now(),
+                                 display_name=user.display_name,
+                                 email=email, week=week,
+                                 text=text, private=private,
+                                 is_markdown=is_markdown)
+    snippet.put()
 
 
-class UpdateSnippet(BaseHandler):
-    def update_snippet(self, email):
-        week_string = self.request.get('week')
+@app.route("/update_snippet", methods=["POST"])
+def update_snippet_handler_post():
+    """Handle ajax updates via POST.
+
+    In particular, return status via json rather than redirects and hard
+    exceptions. This isn't actually RESTy, it's just status codes and json.
+    """
+
+    data = flask.request.form
+    week_string = data.get('week', '')
+    text = data.get('snippet', '')
+    private = data.get('private') == 'True'
+    is_markdown = data.get('is_markdown') == 'True'
+
+    # TODO(marcos): consider using PUT?
+
+    if not users.get_current_user():
+        return flask.make_response(
+            {"status": 401, "message": "not logged in"}, 401)
+
+    email = data.get('u', _current_user_email())
+    if not _logged_in_user_has_permission_for(email):
+        # TODO(marcos): present these messages to the ajax client
+        error = ('You do not have permissions to update user'
+                 ' snippets for %s' % email)
+        return flask.make_response({"status": 403, "message": error}, 403)
+
+    try:
         week = datetime.datetime.strptime(week_string, '%m-%d-%Y').date()
-        assert week.weekday() == 0, 'passed-in date must be a Monday'
-
-        text = self.request.get('snippet')
-
-        private = self.request.get('private') == 'True'
-        is_markdown = self.request.get('is_markdown') == 'True'
-
-        # TODO(csilvers): make this get-update-put atomic.
-        # (maybe make the snippet id be email + week).
-        q = models.Snippet.all()
-        q.filter('email = ', email)
-        q.filter('week = ', week)
-        snippet = q.get()
-
-        # When adding a snippet, make sure we create a user record for
-        # that email as well, if it doesn't already exist.
-        user = _get_or_create_user(email)
-
-        # Store user's display_name in snippet so that if a user is later
-        # deleted, we could still show his / her display_name.
-        if snippet:
-            snippet.text = text   # just update the snippet text
-            snippet.display_name = user.display_name
-            snippet.private = private
-            snippet.is_markdown = is_markdown
-        else:
-            # add the snippet to the db
-            snippet = models.Snippet(created=_TODAY_FN(),
-                                     display_name=user.display_name,
-                                     email=email, week=week,
-                                     text=text, private=private,
-                                     is_markdown=is_markdown)
-        db.put(snippet)
-        db.get(snippet.key())  # ensure db consistency for HRD
-
-        self.response.set_status(200)
-
-    def post(self):
-        """handle ajax updates via POST
-
-        in particular, return status via json rather than redirects and
-        hard exceptions. This isn't actually RESTy, it's just status
-        codes and json.
-        """
-        # TODO(marcos): consider using PUT?
-
-        self.response.headers['Content-Type'] = 'application/json'
-
-        if not users.get_current_user():
-            # 403s are the catch-all 'please log in error' here
-            self.response.set_status(403)
-            self.response.out.write('{"status": 403, '
-                                    '"message": "not logged in"}')
-            return
-
-        email = self.request.get('u', _current_user_email())
-
-        if not _logged_in_user_has_permission_for(email):
-            # TODO(marcos): present these messages to the ajax client
-            self.response.set_status(403)
-            error = ('You do not have permissions to update user'
-                     ' snippets for %s' % email)
-            self.response.out.write('{"status": 403, '
-                                    '"message": "%s"}' % error)
-            return
-
-        self.update_snippet(email)
-        self.response.out.write('{"status": 200, "message": "ok"}')
-
-    def get(self):
-        if not users.get_current_user():
-            return _login_page(self.request, self)
-
-        email = self.request.get('u', _current_user_email())
-        if not _logged_in_user_has_permission_for(email):
-            # TODO(csilvers): return a 403 here instead.
-            raise RuntimeError('You do not have permissions to update user'
-                               ' snippets for %s' % email)
-
-        self.update_snippet(email)
-
-        email = self.request.get('u', _current_user_email())
-        self.redirect("/?msg=Snippet+saved&u=%s" % urllib.quote(email))
-
-
-class Settings(BaseHandler):
-    """Page to display a user's settings (from class User) for modification."""
+    except (ValueError, TypeError):
+        return flask.make_response(
+            {"status": 400,
+             "message": "Invalid week. Expected format: MM-DD-YYYY"},
+            400)
 
-    def get(self):
-        if not users.get_current_user():
-            return _login_page(self.request, self)
-
-        user_email = self.request.get('u', _current_user_email())
-        if not _logged_in_user_has_permission_for(user_email):
-            # TODO(csilvers): return a 403 here instead.
-            raise RuntimeError('You do not have permissions to view user'
-                               ' settings for %s' % user_email)
-        # We won't put() the new user until the settings are saved.
-        user = _get_or_create_user(user_email, put_new_user=False)
-        try:
-            user.key()
-            is_new_user = False
-        except db.NotSavedError:
-            is_new_user = True
+    try:
+        update_snippet(email, week, text, private, is_markdown)
+    except AssertionError as err:
+        return flask.make_response({"status": 400, "message": err}, 400)
 
-        template_values = {
-            'logout_url': users.create_logout_url('/'),
-            'message': self.request.get('msg'),
-            'username': user.email,
-            'is_admin': users.is_current_user_admin(),
-            'view_week': util.existingsnippet_monday(_TODAY_FN()),
-            'user': user,
-            'is_new_user': is_new_user,
-            'redirect_to': self.request.get('redirect_to', ''),
-            # We could get this from user, but we want to replace
-            # commas with newlines for printing.
-            'wants_to_view': user.wants_to_view.replace(',', '\n'),
-        }
-        self.render_response('settings.html', template_values)
+    return flask.make_response({"status": 200, "message": "ok"})
 
 
-class UpdateSettings(BaseHandler):
-    """Updates the db with modifications from the Settings page."""
+@app.route("/update_snippet", methods=["GET"])
+def update_snippet_handler_get():
+    data = flask.request.args
+    week_string = data.get('week', '')
+    text = data.get('snippet', '')
+    private = data.get('private') == 'True'
+    is_markdown = data.get('is_markdown') == 'True'
 
-    def get(self):
-        if not users.get_current_user():
-            return _login_page(self.request, self)
-
-        user_email = self.request.get('u', _current_user_email())
-        if not _logged_in_user_has_permission_for(user_email):
-            # TODO(csilvers): return a 403 here instead.
-            raise RuntimeError('You do not have permissions to modify user'
-                               ' settings for %s' % user_email)
-        # TODO(csilvers): make this get/update/put atomic (put in a txn)
-        user = _get_or_create_user(user_email)
-
-        # First, check if the user clicked on 'delete' or 'hide'
-        # rather than 'save'.
-        if self.request.get('hide'):
-            user.is_hidden = True
-            user.put()
-            time.sleep(0.1)   # some time for eventual consistency
-            self.redirect('/weekly?msg=You+are+now+hidden.+Have+a+nice+day!')
-            return
-        elif self.request.get('delete'):
-            db.delete(user)
-            self.redirect('/weekly?msg=Your+account+has+been+deleted.+'
-                          '(Note+your+existing+snippets+have+NOT+been+'
-                          'deleted.)+Have+a+nice+day!')
-            return
-
-        display_name = self.request.get('display_name')
-        category = self.request.get('category')
-        uses_markdown = self.request.get('markdown') == 'yes'
-        private_snippets = self.request.get('private') == 'yes'
-        wants_email = self.request.get('reminder_email') == 'yes'
-
-        # We want this list to be comma-separated, but people are
-        # likely to use whitespace to separate as well.  Convert here.
-        wants_to_view = self.request.get('to_view')
-        wants_to_view = re.sub(r'\s+', ',', wants_to_view)
-        wants_to_view = wants_to_view.split(',')
-        wants_to_view = [w for w in wants_to_view if w]   # deal with ',,'
-        wants_to_view = ','.join(wants_to_view)  # TODO(csilvers): keep as list
-
-        # Changing their settings is the kind of activity that unhides
-        # someone who was hidden, unless they specifically ask to be
-        # hidden.
-        is_hidden = self.request.get('is_hidden', 'no') == 'yes'
-
-        user.is_hidden = is_hidden
-        user.display_name = display_name
-        user.category = category or models.NULL_CATEGORY
-        user.uses_markdown = uses_markdown
-        user.private_snippets = private_snippets
-        user.wants_email = wants_email
-        user.wants_to_view = wants_to_view
-        db.put(user)
-        db.get(user.key())  # ensure db consistency for HRD
-
-        redirect_to = self.request.get('redirect_to')
-        if redirect_to == 'snippet_entry':   # true for new_user.html
-            self.redirect('/?u=%s' % urllib.quote(user_email))
-        else:
-            self.redirect("/settings?msg=Changes+saved&u=%s"
-                          % urllib.quote(user_email))
+    if not users.get_current_user():
+        return _login_page(flask.request)
 
+    email = data.get('u', _current_user_email())
+    if not _logged_in_user_has_permission_for(email):
+        # TODO(benley): Add a friendlier error page template, maybe?
+        return flask.make_response("You do not have permission to update"
+                                   " user snippets for %s" % email, 403)
 
-class AppSettings(BaseHandler):
-    """Page to display settings for the whole app, for modification.
+    try:
+        week = datetime.datetime.strptime(week_string, '%m-%d-%Y').date()
+    except (ValueError, TypeError):
+        return flask.make_response(
+            "Invalid week. Expected format: MM-DD-YYYY", 400)
 
-    This page should be restricted to admin users via app.yaml.
-    """
+    try:
+        update_snippet(email, week, text, private, is_markdown)
+    except AssertionError as err:
+        return flask.make_response("Failed to save snippet: %s" % err, 400)
 
-    def get(self):
-        my_domain = _current_user_email().split('@')[-1]
-        app_settings = models.AppSettings.get(create_if_missing=True,
-                                              domains=[my_domain])
+    return flask.redirect(
+        "/?msg=Snippet+saved&u=%s" % urllib.parse.quote(email))
 
-        template_values = {
-            'logout_url': users.create_logout_url('/'),
-            'message': self.request.get('msg'),
-            'username': _current_user_email(),
-            'is_admin': users.is_current_user_admin(),
-            'view_week': util.existingsnippet_monday(_TODAY_FN()),
-            'redirect_to': self.request.get('redirect_to', ''),
-            'settings': app_settings,
-            'slack_slash_commands': (
-                slacklib.command_usage().strip())
-        }
-        self.render_response('app_settings.html', template_values)
 
+@app.route("/settings")
+def settings_handler():
+    """Page to display a user's settings (from class User) for modification."""
 
-class UpdateAppSettings(BaseHandler):
-    """Updates the db with modifications from the App-Settings page.
+    if not users.get_current_user():
+        return _login_page(flask.request)
+
+    user_email = flask.request.args.get('u', _current_user_email())
+    if not _logged_in_user_has_permission_for(user_email):
+        return flask.make_response('You do not have permissions to view user'
+                                   ' settings for %s' % user_email, 403)
+    # We won't put() the new user until the settings are saved.
+    user = _get_or_create_user(user_email, put_new_user=False)
+
+    # TODO(benley): https://stackoverflow.com/questions/12083254/is-it-possible-to-determine-with-ndb-if-model-is-persistent-in-the-datastore-or/12096066#12096066
+    # NOTE: this will break if you explicitly set the key when creating the
+    #       user entity!
+    #       See https://groups.google.com/g/google-appengine/c/Tm8NDWIvc70
+    is_new_user = bool(user.key and user.key.id())
+
+    template_values = {
+        'logout_url': users.create_logout_url('/'),
+        'message': flask.request.args.get('msg'),
+        'username': user.email,
+        'is_admin': users.is_current_user_admin(),
+        'view_week': util.existingsnippet_monday(datetime.datetime.now()),
+        'user': user,
+        'is_new_user': is_new_user,
+        'redirect_to': flask.request.args.get('redirect_to', ''),
+        # We could get this from user, but we want to replace
+        # commas with newlines for printing.
+        'wants_to_view': user.wants_to_view.replace(',', '\n'),
+    }
+    return flask.render_template('settings.html', **template_values)
+
+
+@app.route("/update_settings")
+def update_settings_handler():
+    """Updates the db with modifications from the Settings page."""
+
+    if not users.get_current_user():
+        return _login_page(flask.request)
+
+    user_email = flask.request.args.get('u', _current_user_email())
+    if not _logged_in_user_has_permission_for(user_email):
+        return flask.make_response('You do not have permissions to modify user'
+                                   ' settings for %s' % user_email, 403)
+    # TODO(csilvers): make this get/update/put atomic (put in a txn)
+    user = _get_or_create_user(user_email)
+
+    # First, check if the user clicked on 'delete' or 'hide'
+    # rather than 'save'.
+    if flask.request.args.get('hide'):
+        user.is_hidden = True
+        user.put()
+        return flask.redirect('/weekly?msg=You+are+now+hidden.+Have+a+nice+day!')
+    elif flask.request.args.get('delete'):
+        user.key.delete()
+        return flask.redirect('/weekly?msg=Your+account+has+been+deleted.+'
+                              '(Note+your+existing+snippets+have+NOT+been+'
+                              'deleted.)+Have+a+nice+day!')
+
+    display_name = flask.request.args.get('display_name')
+    category = flask.request.args.get('category')
+    slack_id = flask.request.args.get('slack_id')
+    uses_markdown = flask.request.args.get('markdown') == 'yes'
+    private_snippets = flask.request.args.get('private') == 'yes'
+    wants_email = flask.request.args.get('reminder_email') == 'yes'
+
+    # We want this list to be comma-separated, but people are
+    # likely to use whitespace to separate as well.  Convert here.
+    wants_to_view = flask.request.args.get('to_view', '')
+    wants_to_view = re.sub(r'\s+', ',', wants_to_view)
+    wants_to_view = wants_to_view.split(',')
+    wants_to_view = [w for w in wants_to_view if w]   # deal with ',,'
+    wants_to_view = ','.join(wants_to_view)  # TODO(csilvers): keep as list
+
+    # Changing their settings is the kind of activity that unhides
+    # someone who was hidden, unless they specifically ask to be
+    # hidden.
+    is_hidden = flask.request.args.get('is_hidden', 'no') == 'yes'
+
+    user.is_hidden = is_hidden
+    user.display_name = display_name
+    user.category = category or models.NULL_CATEGORY
+    user.slack_id = slack_id
+    user.uses_markdown = uses_markdown
+    user.private_snippets = private_snippets
+    user.wants_email = wants_email
+    user.wants_to_view = wants_to_view
+    user.put()
+
+    redirect_to = flask.request.args.get('redirect_to')
+    if redirect_to == 'snippet_entry':   # true for new_user.html
+        return flask.redirect('/?u=%s' % urllib.parse.quote(user_email))
+    else:
+        return flask.redirect("/settings?msg=Changes+saved&u=%s"
+                              % urllib.parse.quote(user_email))
+
+
+@app.route("/admin/settings")
+def admin_settings_handler():
+    """Page to display settings for the whole app, for modification.
 
     This page should be restricted to admin users via app.yaml.
     """
+    my_domain = _current_user_email().split('@')[-1]
+    app_settings = models.AppSettings.get(create_if_missing=True,
+                                            domains=[my_domain])
+
+    template_values = {
+        'logout_url': users.create_logout_url('/'),
+        'message': flask.request.args.get('msg'),
+        'username': _current_user_email(),
+        'is_admin': users.is_current_user_admin(),
+        'view_week': util.existingsnippet_monday(datetime.datetime.now()),
+        'redirect_to': flask.request.args.get('redirect_to', ''),
+        'settings': app_settings,
+        'slack_slash_commands': slacklib.command_usage().strip()
+    }
+    return flask.render_template('app_settings.html', **template_values)
+
+
+@app.route("/admin/update_settings", methods=["POST"])
+def admin_update_settings_handler():
+    """Updates the db with modifications from the App-Settings page.
 
-    def get(self):
-        _get_or_create_user(_current_user_email())
-
-        domains = self.request.get('domains')
-        default_private = self.request.get('private') == 'yes'
-        default_markdown = self.request.get('markdown') == 'yes'
-        default_email = self.request.get('reminder_email') == 'yes'
-        email_from = self.request.get('email_from')
-        slack_channel = self.request.get('slack_channel')
-        slack_token = self.request.get('slack_token')
-        slack_slash_token = self.request.get('slack_slash_token')
-
-        # Turn domains into a list.  Allow whitespace or comma to separate.
-        domains = re.sub(r'\s+', ',', domains)
-        domains = [d for d in domains.split(',') if d]
-
-        @db.transactional
-        def update_settings():
-            app_settings = models.AppSettings.get(create_if_missing=True,
-                                                  domains=domains)
-            app_settings.domains = domains
-            app_settings.default_private = default_private
-            app_settings.default_markdown = default_markdown
-            app_settings.default_email = default_email
-            app_settings.email_from = email_from
-            app_settings.slack_channel = slack_channel
-            app_settings.slack_token = slack_token
-            app_settings.slack_slash_token = slack_slash_token
-            app_settings.put()
-
-        update_settings()
-
-        redirect_to = self.request.get('redirect_to')
-        if redirect_to == 'user_setting':   # true for new_user.html
-            self.redirect('/settings?redirect_to=snippet_entry'
-                          '&msg=Now+enter+your+personal+user+settings.')
-        else:
-            self.redirect("/admin/settings?msg=Changes+saved")
+    This page should be restricted to admin users via app.yaml.
+    """
+    domains = flask.request.form.get('domains')
+    default_private = flask.request.form.get('private') == 'yes'
+    default_markdown = flask.request.form.get('markdown') == 'yes'
+    default_email = flask.request.form.get('reminder_email') == 'yes'
+    email_from = flask.request.form.get('email_from')
+    hipchat_room = flask.request.form.get('hipchat_room')
+    hipchat_token = flask.request.form.get('hipchat_token')
+    hostname = flask.request.form.get('hostname')
+    slack_channel = flask.request.form.get('slack_channel')
+    slack_token = flask.request.form.get('slack_token')
+    slack_slash_token = flask.request.form.get('slack_slash_token')
+
+    # Turn domains into a list.  Allow whitespace or comma to separate.
+    domains = re.sub(r'\s+', ',', domains)
+    domains = [d for d in domains.split(',') if d]
+
+    @ndb.transactional()
+    def update_settings():
+        app_settings = models.AppSettings.get(create_if_missing=True,
+                                              domains=domains)
+        app_settings.domains = domains
+        app_settings.default_private = default_private
+        app_settings.default_markdown = default_markdown
+        app_settings.default_email = default_email
+        app_settings.email_from = email_from
+        app_settings.hostname = hostname
+        app_settings.slack_channel = slack_channel
+        app_settings.slack_token = slack_token
+        app_settings.slack_slash_token = slack_slash_token
+        app_settings.put()
+
+    update_settings()
+
+    _get_or_create_user(_current_user_email())
+
+    redirect_to = flask.request.form.get('redirect_to')
+    if redirect_to == 'user_setting':   # true for new_user.html
+        return flask.redirect('/settings?redirect_to=snippet_entry'
+                              '&msg=Now+enter+your+personal+user+settings.')
+    else:
+        return flask.redirect("/admin/settings?msg=Changes+saved")
 
 
-class ManageUsers(BaseHandler):
+@app.route("/admin/manage_users", methods=["GET", "POST"])
+def admin_manage_users_handler():
     """Lets admins delete and otherwise manage users."""
-
-    def get(self):
-        # options are 'email', 'creation_time', 'last_snippet_time'
-        sort_by = self.request.get('sort_by', 'creation_time')
-
-        # First, check if the user had clicked on a button.
-        for (name, value) in self.request.params.iteritems():
-            if name.startswith('hide '):
-                email_of_user_to_hide = name[len('hide '):]
-                # TODO(csilvers): move this get/update/put atomic into a txn
-                user = util.get_user_or_die(email_of_user_to_hide)
-                user.is_hidden = True
-                user.put()
-                time.sleep(0.1)   # encourage eventual consistency
-                self.redirect('/admin/manage_users?sort_by=%s&msg=%s+hidden'
-                              % (sort_by, email_of_user_to_hide))
-                return
-            if name.startswith('unhide '):
-                email_of_user_to_unhide = name[len('unhide '):]
-                # TODO(csilvers): move this get/update/put atomic into a txn
-                user = util.get_user_or_die(email_of_user_to_unhide)
-                user.is_hidden = False
-                user.put()
-                time.sleep(0.1)   # encourage eventual consistency
-                self.redirect('/admin/manage_users?sort_by=%s&msg=%s+unhidden'
-                              % (sort_by, email_of_user_to_unhide))
-                return
-            if name.startswith('delete '):
-                email_of_user_to_delete = name[len('delete '):]
-                user = util.get_user_or_die(email_of_user_to_delete)
-                db.delete(user)
-                time.sleep(0.1)   # encourage eventual consistency
-                self.redirect('/admin/manage_users?sort_by=%s&msg=%s+deleted'
-                              % (sort_by, email_of_user_to_delete))
-                return
-
-        user_q = models.User.all()
-        results = user_q.fetch(1000)
-
-        # Tuple: (email, is-hidden, creation-time, days since last snippet)
-        user_data = []
-        for user in results:
-            # Get the last snippet for that user.
-            last_snippet = util.most_recent_snippet_for_user(user.email)
-            if last_snippet:
-                seconds_since_snippet = (
-                    (_TODAY_FN().date() - last_snippet.week).total_seconds())
-                weeks_since_snippet = int(
-                    seconds_since_snippet /
-                    datetime.timedelta(days=7).total_seconds())
-            else:
-                weeks_since_snippet = None
-            user_data.append((user.email, user.is_hidden,
-                              user.created, weeks_since_snippet))
-
-        # We have to use 'cmp' here since we want ascending in the
-        # primary key and descending in the secondary key, sometimes.
-        if sort_by == 'email':
-            user_data.sort(lambda x, y: cmp(x[0], y[0]))
-        elif sort_by == 'creation_time':
-            user_data.sort(lambda x, y: (-cmp(x[2] or datetime.datetime.min,
-                                              y[2] or datetime.datetime.min)
-                                         or cmp(x[0], y[0])))
-        elif sort_by == 'last_snippet_time':
-            user_data.sort(lambda x, y: (-cmp(1000 if x[3] is None else x[3],
-                                              1000 if y[3] is None else y[3])
-                                         or cmp(x[0], y[0])))
+    # options are 'email', 'creation_time', 'last_snippet_time'
+    sort_by = flask.request.args.get('sort_by', 'creation_time')
+
+    # First, check if the user had clicked on a button.
+    if flask.request.form.get("action") == "hide":
+        email_of_user_to_hide = flask.request.form.get("email")
+        # TODO(csilvers): move this get/update/put atomic into a txn
+        user = util.get_user_or_die(email_of_user_to_hide)
+        user.is_hidden = True
+        user.put()
+        logging.info("Hide user: %s", user.email)
+        return flask.redirect('/admin/manage_users?sort_by=%s&msg=%s+hidden'
+                              % (sort_by, user.email))
+    elif flask.request.form.get("action") == "unhide":
+        email_of_user_to_unhide = flask.request.form.get("email")
+        # TODO(csilvers): move this get/update/put atomic into a txn
+        user = util.get_user_or_die(email_of_user_to_unhide)
+        user.is_hidden = False
+        user.put()
+        logging.info("Unhide user: %s", user.email)
+        return flask.redirect('/admin/manage_users?sort_by=%s&msg=%s+unhidden'
+                              % (sort_by, user.email))
+    elif flask.request.form.get("action") == "delete":
+        email_of_user_to_delete = flask.request.form.get("email")
+        user = util.get_user_or_die(email_of_user_to_delete)
+        user.key.delete()
+        logging.info("Delete user: %s", user.email)
+        return flask.redirect('/admin/manage_users?sort_by=%s&msg=%s+deleted'
+                              % (sort_by, user.email))
+
+    user_q = models.User.query()
+    results = user_q.fetch(1000)
+
+    now = datetime.datetime.now()
+
+    # Tuple: (email, is-hidden, creation-time, days since last snippet)
+    user_data = []
+    for user in results:
+        # Get the last snippet for that user.
+        last_snippet = util.most_recent_snippet_for_user(user.email)
+        if last_snippet:
+            seconds_since_snippet = (now.date() -
+                                     last_snippet.week).total_seconds()
+            weeks_since_snippet = int(
+                seconds_since_snippet /
+                datetime.timedelta(days=7).total_seconds())
         else:
-            raise ValueError('Invalid sort_by value "%s"' % sort_by)
+            weeks_since_snippet = None
+        user_data.append((user.email, user.is_hidden,
+                          user.created, weeks_since_snippet))
+
+    if sort_by == 'email':
+        user_data.sort(key=lambda x: x[0])
+    elif sort_by == 'creation_time':
+        user_data.sort(key=lambda x: x[0])
+        user_data.sort(key=lambda x: x[2] or datetime.datetime.min, reverse=True)
+    elif sort_by == 'last_snippet_time':
+        user_data.sort(key=lambda x: x[0])
+        user_data.sort(key=lambda x: 1000 if x[3] is None else x[3], reverse=True)
+    else:
+        raise ValueError('Invalid sort_by value "%s"' % sort_by)
 
-        template_values = {
-            'logout_url': users.create_logout_url('/'),
-            'message': self.request.get('msg'),
-            'username': _current_user_email(),
-            'is_admin': users.is_current_user_admin(),
-            'view_week': util.existingsnippet_monday(_TODAY_FN()),
-            'user_data': user_data,
-            'sort_by': sort_by,
-        }
-        self.render_response('manage_users.html', template_values)
+    template_values = {
+        'logout_url': users.create_logout_url('/'),
+        'message': flask.request.args.get('msg'),
+        'username': _current_user_email(),
+        'is_admin': users.is_current_user_admin(),
+        'view_week': util.existingsnippet_monday(now),
+        'user_data': user_data,
+        'sort_by': sort_by,
+    }
+    return flask.render_template('manage_users.html', **template_values)
 
 
 # The following two classes are called by cron.
 
 
-def _get_email_to_current_snippet_map(today):
+def _get_email_to_current_snippet_map(today: datetime.datetime) -> dict[str, bool]:
     """Return a map from email to True if they've written snippets this week.
 
     Goes through all users registered on the system, and checks if
@@ -686,7 +699,7 @@ def _get_email_to_current_snippet_map(today):
       a map from email (user.email for each user) to True or False,
       depending on if they've written snippets for this week or not.
     """
-    user_q = models.User.all()
+    user_q = models.User.query()
     users = user_q.fetch(1000)
     retval = {}
     for user in users:
@@ -695,8 +708,9 @@ def _get_email_to_current_snippet_map(today):
         retval[user.email] = False       # assume the worst, for now
 
     week = util.existingsnippet_monday(today)
-    snippets_q = models.Snippet.all()
-    snippets_q.filter('week = ', week)
+    snippets_q = models.Snippet.query(
+        models.Snippet.week == week
+    )
     snippets = snippets_q.fetch(1000)
     for snippet in snippets:
         if snippet.email in retval:      # don't introduce new keys here
@@ -716,12 +730,11 @@ def _maybe_send_snippets_mail(to, subject, template_path, template_values):
 
     template_values.setdefault('hostname', app_settings.hostname)
 
-    jinja2_instance = jinja2.get_jinja2()
     mail.send_mail(sender=app_settings.email_from,
                    to=to,
                    subject=subject,
-                   body=jinja2_instance.render_template(template_path,
-                                                        **template_values))
+                   body=flask.render_template(template_path,
+                                              **template_values))
     # Appengine has a quota of 32 emails per minute:
     #    https://developers.google.com/appengine/docs/quotas#Mail
     # We pause 2 seconds between each email to make sure we
@@ -729,66 +742,62 @@ def _maybe_send_snippets_mail(to, subject, template_path, template_values):
     time.sleep(2)
 
 
-class SendFridayReminderChat(BaseHandler):
+@app.route("/admin/send_friday_reminder_chat")
+def admin_send_friday_reminder_chat_handler() -> flask.Response:
     """Send a chat message to the configured chat room(s)."""
-
-    def get(self):
-        msg = 'Reminder: Weekly snippets due Monday at 5pm.'
-        _send_to_chat(msg, "/")
+    msg = 'Reminder: Weekly snippets due Monday at 5pm.'
+    _send_to_chat(msg, "/")
+    return flask.make_response({"status": 200, "message": "Sent friday reminder chat"})
 
 
-class SendReminderEmail(BaseHandler):
+@app.route("/admin/send_reminder_email")
+def admin_send_reminder_email_handler() -> flask.Response:
     """Send an email to everyone who doesn't have a snippet for this week."""
 
-    def _send_mail(self, email):
+    def _send_mail(email):
         template_values = {}
         _maybe_send_snippets_mail(email, 'Weekly snippets due today at 5pm',
                                   'reminder_email.txt', template_values)
 
-    def get(self):
-        email_to_has_snippet = _get_email_to_current_snippet_map(_TODAY_FN())
-        for (user_email, has_snippet) in email_to_has_snippet.iteritems():
-            if not has_snippet:
-                self._send_mail(user_email)
-                logging.debug('sent reminder email to %s' % user_email)
-            else:
-                logging.debug('did not send reminder email to %s: '
-                              'has a snippet already' % user_email)
+    email_to_has_snippet = _get_email_to_current_snippet_map(
+        datetime.datetime.now())
+    for user_email, has_snippet in email_to_has_snippet.items():
+        if not has_snippet:
+            _send_mail(user_email)
+            logging.debug('sent reminder email to %s', user_email)
+        else:
+            logging.debug('did not send reminder email to %s: '
+                          'has a snippet already', user_email)
 
-        msg = 'Reminder: Weekly snippets due today at 5pm.'
-        _send_to_chat(msg, "/")
+    msg = 'Reminder: Weekly snippets due today at 5pm.'
+    _send_to_chat(msg, "/")
+    return flask.make_response({"status": 200, "message": "Sent reminder emails"})
 
 
-class SendViewEmail(BaseHandler):
+@app.route("/admin/send_view_email")
+def admin_send_view_email_handler() -> flask.Response:
     """Send an email to everyone to look at the week's snippets."""
 
-    def _send_mail(self, email, has_snippets):
+    def _send_mail(email, has_snippets):
         template_values = {'has_snippets': has_snippets}
         _maybe_send_snippets_mail(email, 'Weekly snippets are ready!',
                                   'view_email.txt', template_values)
 
-    def get(self):
-        email_to_has_snippet = _get_email_to_current_snippet_map(_TODAY_FN())
-        for (user_email, has_snippet) in email_to_has_snippet.iteritems():
-            self._send_mail(user_email, has_snippet)
-            logging.debug('sent "view" email to %s' % user_email)
-
-        msg = 'Weekly snippets are ready!'
-        _send_to_chat(msg, "/weekly")
-
-
-application = webapp2.WSGIApplication([
-    ('/', UserPage),
-    ('/weekly', SummaryPage),
-    ('/update_snippet', UpdateSnippet),
-    ('/settings', Settings),
-    ('/update_settings', UpdateSettings),
-    ('/admin/settings', AppSettings),
-    ('/admin/update_settings', UpdateAppSettings),
-    ('/admin/manage_users', ManageUsers),
-    ('/admin/send_friday_reminder_chat', SendFridayReminderChat),
-    ('/admin/send_reminder_email', SendReminderEmail),
-    ('/admin/send_view_email', SendViewEmail),
-    ('/slack', slacklib.SlashCommand),
-    ],
-    debug=True)
+    email_to_has_snippet = _get_email_to_current_snippet_map(
+        datetime.datetime.now())
+    for user_email, has_snippet in email_to_has_snippet.items():
+        _send_mail(user_email, has_snippet)
+        logging.debug('sent "view" email to %s', user_email)
+
+    msg = 'Weekly snippets are ready!'
+    _send_to_chat(msg, "/weekly")
+    return flask.make_response({"status": 200, "message": "Sent 'snippets are ready' emails"})
+
+
+@app.route('/_ah/warmup')
+def warmup():
+    """App engine warmup requests handler
+
+    See https://cloud.google.com/appengine/docs/standard/configuring-warmup-requests?tab=python
+    """
+    return "OK", 200, {}
diff --git a/snippets_test.py b/snippets_test.py
index 19d9e05..9ad9d4e 100755
--- a/snippets_test.py
+++ b/snippets_test.py
@@ -1,57 +1,44 @@
 #!/usr/bin/env python
+# -*- coding: utf-8 -*-
 
 """Tests for the snippets server.
 
 This tests the functionality found at weekly-snippets.appspot.com.
 
 c.f. http://code.google.com/appengine/docs/python/tools/localunittesting.html
-c.f. http://webtest.pythonpaste.org/en/latest/index.html
+     https://flask.palletsprojects.com/en/2.2.x/testing/
+     https://docs.pytest.org/en/7.1.x/how-to/unittest.html
+     https://github.com/adamchainz/time-machine
 """
 
 __author__ = 'Craig Silverstein <csilvers@khanacademy.org>'
 
-
 import datetime
-import os
 import re
-import sys
 import time
-try:   # Work under either python2.5 or python2.7
-    import unittest2 as unittest
-except ImportError:
-    import unittest
-
-# Update sys.path so it can find these.  We just need to add
-# 'google_appengine', but we add all of $PATH to be easy.  This
-# assumes the google_appengine directory is on the path.
-sys.path.extend(os.environ['PATH'].split(':'))
-import dev_appserver
-dev_appserver.fix_sys_path()
-
-from google.appengine.datastore import datastore_stub_util
-from google.appengine.ext import db
+import unittest
+from typing import AnyStr, Pattern
+import warnings
+from zoneinfo import ZoneInfo
+
+from google.cloud import ndb
 from google.appengine.ext import testbed
-import webtest   # may need to do 'pip install webtest'
+import time_machine
 
 import models
 import slacklib
 import snippets
 
 
-_TEST_TODAY = datetime.datetime(2012, 2, 23)
-
-
+# Today's pretend date is Thursday, Feb 23, 2012
+@time_machine.travel(datetime.datetime(2012, 2, 23, tzinfo=ZoneInfo("UTC")))
 class SnippetsTestBase(unittest.TestCase):
     def setUp(self):
-        # We're not interested in testing consistency stuff in these tests.
         self.testbed = testbed.Testbed()
         self.testbed.activate()
-        policy = datastore_stub_util.PseudoRandomHRConsistencyPolicy(
-            probability=1)
-        self.testbed.init_datastore_v3_stub(consistency_policy=policy)
         self.testbed.init_user_stub()
-        self.request_fetcher = webtest.TestApp(snippets.application)
-        snippets._TODAY_FN = lambda: _TEST_TODAY
+
+        self.request_fetcher = snippets.app.test_client()
 
         # Make sure we never accidentally send messages to chat.
         self.old_send_to_slack_channel = slacklib.send_to_slack_channel
@@ -64,9 +51,12 @@ def tearDown(self):
         slacklib.send_to_slack_channel = self.old_send_to_slack_channel
 
     def login(self, email):
-        self.testbed.setup_env(user_email=email, overwrite=True)
-        self.testbed.setup_env(user_id=email, overwrite=True)
-        self.testbed.setup_env(user_is_admin='0', overwrite=True)
+        self.testbed.setup_env(
+            user_email=email,
+            user_id=email,
+            user_is_admin='0',
+            overwrite=True
+        )
         # Now make sure there are global settings.
         settings = models.AppSettings.get(
             create_if_missing=True,
@@ -78,6 +68,18 @@ def login(self, email):
     def set_is_admin(self):
         self.testbed.setup_env(user_is_admin='1', overwrite=True)
 
+    def assertDictContainsSubset(self, subset, dictionary, msg=None):
+        """Checks whether dictionary is a superset of subset.
+
+        Suppresses the deprecation warning from upstream.
+        """
+        with warnings.catch_warnings():
+            warnings.filterwarnings("ignore", category=DeprecationWarning)
+            # If python upstream removes this function entirely, you can substitute
+            # this in a pinch:
+            # self.assertLessEqual(subset.items(), dictionary.items(), msg)
+            super().assertDictContainsSubset(subset, dictionary, msg)
+
     def assertNumSnippets(self, body, expected_count):
         """Assert the page 'body' has exactly expected_count snippets in it."""
         # We annotate the div at the beginning of each snippet with
@@ -118,26 +120,42 @@ def assertNotInSnippet(self, text, body, snippet_number):
         """For snippet-page 'body', assert 'text' is not in the ith snippet."""
         self.assertNotIn(text, self._ith_snippet(body, snippet_number))
 
+    def assertSnippetRegex(self, regex: AnyStr | Pattern[AnyStr], body, snippet_number):
+        """For snippet-page 'body', assert 'regex' matches the i-th snippet.
+
+        This works for both user-pages and weekly-pages -- we figure out the
+        boundaries of the snippets, and check whether the regex matches the
+        given snippet.
+
+        Arguments:
+           regex: regular expression to match against the snippet
+           body: the full html page
+           snippet_number: which snippet on the page to examine.
+             Index starts at 0.
+        """
+        self.assertRegex(self._ith_snippet(body, snippet_number), regex)
+
 
 class UserTestBase(SnippetsTestBase):
     """The most common base: someone who is logged in as user@example.com."""
     def setUp(self):
-        super(UserTestBase, self).setUp()
+        super().setUp()
         self.login('user@example.com')
 
 
 class PostTestCase(SnippetsTestBase):
     """test the correct output from the server when POSTing"""
 
-    def testPostSnippet(self):
+    def testPostSnippetNormal(self):
         self.login('user@example.com')
         url = '/update_snippet'
         params = {
             'week': '02-20-2012',
             'snippet': 'my inspired snippet'
         }
-        response = self.request_fetcher.post(url, params, status=200)
-        self.assertIn('{"status": 200, "message": "ok"}', response)
+        response = self.request_fetcher.post(url, data=params)
+        self.assertEqual(response.status_code, 200)
+        self.assertDictContainsSubset({"status": 200, "message": "ok"}, response.json)
 
     def testPostSnippetAsOtherPerson(self):
         self.login('user@example.com')
@@ -147,9 +165,10 @@ def testPostSnippetAsOtherPerson(self):
             'snippet': 'my fallacious snippet',
             'u': 'joeuser@example.com'
         }
-        response = self.request_fetcher.post(url, params, status=403)
-        self.assertIn('"status": 403', response)
-        self.assertIn('joeuser@example.com', response)
+        response = self.request_fetcher.post(url, data=params)
+        self.assertEqual(response.status_code, 403)
+        self.assertDictContainsSubset({"status": 403}, response.json)
+        self.assertIn('joeuser@example.com', response.text)
 
     def testPostSnippetNotLoggedIn(self):
         url = '/update_snippet'
@@ -158,9 +177,10 @@ def testPostSnippetNotLoggedIn(self):
             'snippet': 'my fallacious snippet',
             'u': 'user@example.com'
         }
-        response = self.request_fetcher.post(url, params, status=403)
-        self.assertIn('"status": 403', response)
-        self.assertIn('"message": "not logged in"', response)
+        response = self.request_fetcher.post(url, data=params)
+        self.assertEqual(response.status_code, 401)
+        self.assertDictContainsSubset({"status": 401}, response.json)
+        self.assertDictContainsSubset({"message": "not logged in"}, response.json)
 
     def testPostSnippetIsolation(self):
         # updating a single snippet via POST should not affect other snippets
@@ -180,14 +200,15 @@ def testPostSnippetIsolation(self):
             'week': '02-27-2012',
             'snippet': 'updated second snippet'
         }
-        self.request_fetcher.post(url, params, status=200)
+        response = self.request_fetcher.post(url, data=params)
+        self.assertEqual(response.status_code, 200)
 
         # make sure only the second snippet changed
         response = self.request_fetcher.get('/')
-        self.assertInSnippet('>my third snippet<', response.body, 0)
-        self.assertInSnippet('>updated second snippet<', response.body, 1)
-        self.assertNotInSnippet('>my second snippet<', response.body, 1)
-        self.assertInSnippet('>my snippet<', response.body, 2)
+        self.assertInSnippet('>my third snippet<', response.text, 0)
+        self.assertInSnippet('>updated second snippet<', response.text, 1)
+        self.assertNotInSnippet('>my second snippet<', response.text, 1)
+        self.assertInSnippet('>my snippet<', response.text, 2)
 
 
 class LoginRequiredTestCase(SnippetsTestBase):
@@ -261,16 +282,19 @@ def testCanViewWeeklyPage(self):
     def testCannotEditOtherSnippets(self):
         url = ('/update_snippet?week=02-20-2012&snippet=my+snippet'
                '&u=notuser@example.com')
-        # Raises an error if we don't get a 500 response (meaning no perm).
-        self.request_fetcher.get(url, status=500)
+        # Raises an error if we don't get a 403 response (meaning no perm).
+        response = self.request_fetcher.get(url)
+        self.assertEqual(response.status_code, 403)
 
     def testCannotViewOtherSettings(self):
         url = '/settings?u=notuser@example.com'
-        self.request_fetcher.get(url, status=500)
+        response = self.request_fetcher.get(url)
+        self.assertEqual(response.status_code, 403)
 
     def testCannotEditOtherSettings(self):
         url = '/update_settings?u=notuser@example.com'
-        self.request_fetcher.get(url, status=500)
+        response = self.request_fetcher.get(url)
+        self.assertEqual(response.status_code, 403)
 
     def testCanEditOwnSnippets(self):
         url = ('/update_snippet?week=02-20-2012&snippet=my+snippet'
@@ -307,65 +331,64 @@ class NewUserTestCase(UserTestBase):
 
     def testNewUserLogin(self):
         response = self.request_fetcher.get('/')
-        self.assertIn('<title>New user</title>', response.body)
+        self.assertIn('<title>New user</title>', response.text)
 
     def testNewUserContinueUrl(self):
         """After verifying settings, we should go back to snippet-entry."""
         response = self.request_fetcher.get('/')
-        m = re.search(r'<a href="(/settings[^"]*)">', response.body)
+        m = re.search(r'<a href="(/settings[^"]*)">', response.text)
         continue_url = m.group(1)
 
         settings_response = self.request_fetcher.get(continue_url)
         self.assertIn('name="redirect_to" value="snippet_entry"',
-                      settings_response.body)
+                      settings_response.text)
 
         # Now kinda-simulate clicking on the submit button.
         done_response = self.request_fetcher.get(
-            '/update_settings?u=user@example.com&redirect_to=snippet_entry')
-        if done_response.status_int in (301, 302, 303, 304):
-            done_response = done_response.follow()
-        self.assertIn('Snippets for user@example.com', done_response.body)
+            '/update_settings?u=user@example.com&redirect_to=snippet_entry',
+            follow_redirects=True
+        )
+        self.assertIn('Snippets for user@example.com', done_response.text)
 
     def testNewAdminWithNoAppSettings(self):
         """The first time someone logs in, we should go to app settings."""
         self.set_is_admin()
         app_settings = models.AppSettings.get()
-        app_settings.delete()
+        app_settings.key.delete()
 
-        response = self.request_fetcher.get('/')
-        if response.status_int in (301, 302, 303, 304):
-            response = response.follow()
-        self.assertIn('<title>Application settings</title>', response.body)
+        response = self.request_fetcher.get('/', follow_redirects=True)
+        self.assertIn('<title>Application settings</title>', response.text)
 
     def testNewAdminContinueUrls(self):
         """We should go from app settings to user settings to snippet."""
         self.set_is_admin()
         app_settings = models.AppSettings.get()
-        app_settings.delete()
+        app_settings.key.delete()
 
-        response = self.request_fetcher.get('/')
-        if response.status_int in (301, 302, 303, 304):
-            response = response.follow()
-        m = re.search(r'name="redirect_to" value="([^"]*)"', response.body)
+        response = self.request_fetcher.get('/', follow_redirects=True)
+        self.assertEqual(response.status_code, 200)
+        m = re.search(r'name="redirect_to" value="([^"]*)"', response.text)
         continue_url = m.group(1)
 
         # Now kinda-simulate clicking on the submit button.
-        done_response = self.request_fetcher.get(
-            '/admin/update_settings?domains=example.com&redirect_to=%s'
-            % continue_url)
-        if done_response.status_int in (301, 302, 303, 304):
-            done_response = done_response.follow()
-        self.assertIn('<title>User settings', done_response.body)
+        done_response = self.request_fetcher.post(
+            '/admin/update_settings',
+            data={"domains": "example.com",
+                  "hostname": "snippets.example.com",
+                  "redirect_to": continue_url},
+            follow_redirects=True
+        )
+        self.assertIn('<title>User settings', done_response.text)
         self.assertIn('name="redirect_to" value="snippet_entry"',
-                      done_response.body)
+                      done_response.text)
 
     def testNewUserWithNoAppSettings(self):
         """For non-admins, we should not offer the app-settings page."""
         app_settings = models.AppSettings.get()
-        app_settings.delete()
+        app_settings.key.delete()
 
         response = self.request_fetcher.get('/')
-        self.assertIn('<title>New user</title>', response.body)
+        self.assertIn('<title>New user</title>', response.text)
 
     def testNewUserInheritsAppDefaults(self):
         app_settings = models.AppSettings.get()
@@ -374,14 +397,14 @@ def testNewUserInheritsAppDefaults(self):
         app_settings.put()
 
         response = self.request_fetcher.get('/')
-        m = re.search(r'<a href="(/settings[^"]*)">', response.body)
+        m = re.search(r'<a href="(/settings[^"]*)">', response.text)
         continue_url = m.group(1)
         settings_response = self.request_fetcher.get(continue_url)
 
-        self.assertRegexpMatches(settings_response.body,
-                                 r'name="markdown"\s+value="yes"\s+checked')
-        self.assertRegexpMatches(settings_response.body,
-                                 r'name="private"\s+value="yes"\s+checked')
+        self.assertRegex(settings_response.text,
+                         r'name="markdown"\s+value="yes"\s+checked')
+        self.assertRegex(settings_response.text,
+                         r'name="private"\s+value="yes"\s+checked')
 
         # Now change the app-defaults and make sure this is reflected in
         # the new-user setup page.
@@ -390,50 +413,55 @@ def testNewUserInheritsAppDefaults(self):
         app_settings.put()
 
         response = self.request_fetcher.get('/')
-        m = re.search(r'<a href="(/settings[^"]*)">', response.body)
+        m = re.search(r'<a href="(/settings[^"]*)">', response.text)
         continue_url = m.group(1)
         settings_response = self.request_fetcher.get(continue_url)
 
-        self.assertRegexpMatches(settings_response.body,
-                                 r'name="markdown"\s+value="no"\s+checked')
-        self.assertRegexpMatches(settings_response.body,
-                                 r'name="private"\s+value="no"\s+checked')
+        self.assertRegex(settings_response.text,
+                         r'name="markdown"\s+value="no"\s+checked')
+        self.assertRegex(settings_response.text,
+                         r'name="private"\s+value="no"\s+checked')
 
     def testNewUserInValidDomain(self):
         self.login('newuser@example.com')
         response = self.request_fetcher.get('/settings')
-        self.assertIn('<title>User settings', response.body)
+        self.assertIn('<title>User settings', response.text)
 
     def testNewUserInInvalidDomain(self):
         """Test you can not register as a new user from a random domain."""
         self.login('newuser@notallowed.com')
         # TODO(csilvers): give a nice error page instead of a 500.
-        self.request_fetcher.get('/settings', status=500)
+        response = self.request_fetcher.get('/settings')
+        self.assertEqual(response.status_code, 500)
 
     def testSettingsPageDoesNotCreateANewUser(self):
         """Only *saving* the settings should create a new user."""
         response = self.request_fetcher.get('/')
-        self.assertIn('<title>New user</title>', response.body)
-        m = re.search(r'<a href="(/settings[^"]*)">', response.body)
+        self.assertIn('<title>New user</title>', response.text)
+        m = re.search(r'<a href="(/settings[^"]*)">', response.text)
         continue_url = m.group(1)
         self.request_fetcher.get(continue_url)    # visit /settings
 
         # Now if we go to / again, we should get the new-user page again
         # because the settings were never saved.
         response = self.request_fetcher.get('/')
-        self.assertIn('<title>New user</title>', response.body)
+        self.assertIn('<title>New user</title>', response.text)
 
 
 class AppSettingsTestCase(UserTestBase):
     """Test the app-settings page."""
 
     def setUp(self):
-        super(AppSettingsTestCase, self).setUp()
+        super().setUp()
         self.set_is_admin()
 
     def testDomainsParsing(self):
-        self.request_fetcher.get(
-            '/admin/update_settings?domains=a.com,b.com++c.com%0Bd.com,%0B')
+        self.request_fetcher.post(
+            '/admin/update_settings',
+            data={
+                "domains": "a.com,b.com\nc.com d.com,",
+                "hostname": "example.com",
+            })
         app_settings = models.AppSettings.get()
         self.assertEqual(['a.com', 'b.com', 'c.com', 'd.com'],
                          app_settings.domains)
@@ -443,12 +471,12 @@ class UserSettingsTestCase(UserTestBase):
     """Test setting and using user settings."""
 
     def assertInputIsChecked(self, name, body, snippet_number):
-        self.assertRegexpMatches(body, r'name="%s" value="True"\s+checked\s*>'
-                                 % name, snippet_number)
+        self.assertRegex(body, r'name="%s" value="True"\s+checked\s*>' % name,
+                         snippet_number)
 
     def assertInputIsNotChecked(self, name, body, snippet_number):
-        self.assertRegexpMatches(body, r'name="%s" value="True"\s*>' % name,
-                                 snippet_number)
+        self.assertRegex(body, r'name="%s" value="True"\s*>' % name,
+                         snippet_number)
 
     def testDefaultUserSettings(self):
         # Make sure the rest of the tests are actually testing
@@ -457,61 +485,61 @@ def testDefaultUserSettings(self):
 
         response = self.request_fetcher.get('/')
         # Neither private nor 'is-markdown' are checked by default.
-        self.assertInputIsNotChecked('private', response.body, 0)
-        self.assertInputIsNotChecked('is_markdown', response.body, 0)
+        self.assertInputIsNotChecked('private', response.text, 0)
+        self.assertInputIsNotChecked('is_markdown', response.text, 0)
 
     def testPrivateUser(self):
         self.request_fetcher.get(
             '/update_settings?u=user@example.com&private=yes')
         response = self.request_fetcher.get('/')
-        self.assertInputIsChecked('private', response.body, 0)
-        self.assertInputIsNotChecked('is_markdown', response.body, 0)
+        self.assertInputIsChecked('private', response.text, 0)
+        self.assertInputIsNotChecked('is_markdown', response.text, 0)
 
     def testMarkdownUser(self):
         self.request_fetcher.get(
             '/update_settings?u=user@example.com&markdown=yes')
         response = self.request_fetcher.get('/')
-        self.assertInputIsNotChecked('private', response.body, 0)
-        self.assertInputIsChecked('is_markdown', response.body, 0)
+        self.assertInputIsNotChecked('private', response.text, 0)
+        self.assertInputIsChecked('is_markdown', response.text, 0)
 
     def testSettingsForFilledInSnippets(self):
         url = '/update_snippet?week=02-21-2011&snippet=old+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 53)
-        self.assertInputIsNotChecked('private', response.body, 9)
-        self.assertInputIsNotChecked('is_markdown', response.body, 9)
-        self.assertInSnippet('old snippet', response.body, 52)
-        self.assertInputIsNotChecked('private', response.body, 52)
-        self.assertInputIsNotChecked('is_markdown', response.body, 52)
+        self.assertNumSnippets(response.text, 53)
+        self.assertInputIsNotChecked('private', response.text, 9)
+        self.assertInputIsNotChecked('is_markdown', response.text, 9)
+        self.assertInSnippet('old snippet', response.text, 52)
+        self.assertInputIsNotChecked('private', response.text, 52)
+        self.assertInputIsNotChecked('is_markdown', response.text, 52)
 
         self.request_fetcher.get(
             '/update_settings?u=user@example.com&markdown=yes')
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 53)
-        self.assertInputIsNotChecked('private', response.body, 9)
-        self.assertInputIsChecked('is_markdown', response.body, 9)
+        self.assertNumSnippets(response.text, 53)
+        self.assertInputIsNotChecked('private', response.text, 9)
+        self.assertInputIsChecked('is_markdown', response.text, 9)
         # But the existing snippet is unaffected.
-        self.assertInSnippet('old snippet', response.body, 52)
-        self.assertInputIsNotChecked('private', response.body, 52)
-        self.assertInputIsNotChecked('is_markdown', response.body, 52)
+        self.assertInSnippet('old snippet', response.text, 52)
+        self.assertInputIsNotChecked('private', response.text, 52)
+        self.assertInputIsNotChecked('is_markdown', response.text, 52)
 
         self.request_fetcher.get(
             '/update_settings?u=user@example.com&private=yes')
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 53)
-        self.assertInputIsChecked('private', response.body, 9)
-        self.assertInputIsNotChecked('is_markdown', response.body, 9)
-        self.assertInSnippet('old snippet', response.body, 52)
-        self.assertInputIsNotChecked('private', response.body, 52)
-        self.assertInputIsNotChecked('is_markdown', response.body, 52)
+        self.assertNumSnippets(response.text, 53)
+        self.assertInputIsChecked('private', response.text, 9)
+        self.assertInputIsNotChecked('is_markdown', response.text, 9)
+        self.assertInSnippet('old snippet', response.text, 52)
+        self.assertInputIsNotChecked('private', response.text, 52)
+        self.assertInputIsNotChecked('is_markdown', response.text, 52)
 
     def testCategoryUnset(self):
         self.request_fetcher.get('/update_settings?u=user@example.com')
         response = self.request_fetcher.get('/')
         self.assertInSnippet(
             '<strong>WARNING:</strong> Snippet will go in the "(unknown)"',
-            response.body, 0
+            response.text, 0
         )
 
     def testCategorySet(self):
@@ -521,7 +549,7 @@ def testCategorySet(self):
         response = self.request_fetcher.get('/')
         self.assertNotInSnippet(
             '<strong>WARNING:</strong> Snippet will go in the "(unknown)"',
-            response.body, 0
+            response.text, 0
         )
 
     def testCategoryUnsetButSnippetHasContent(self):
@@ -531,22 +559,22 @@ def testCategoryUnsetButSnippetHasContent(self):
         response = self.request_fetcher.get('/')
         self.assertInSnippet(
             '<strong>WARNING:</strong> Snippet will go in the "(unknown)"',
-            response.body, 0
+            response.text, 0
         )
 
     def testCategoryCheckForFilledInSnippets(self):
         url = '/update_snippet?week=02-21-2011&snippet=old+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 53)
+        self.assertNumSnippets(response.text, 53)
         self.assertInSnippet(
             '<strong>WARNING:</strong> Snippet will go in the "(unknown)"',
-            response.body, 9
+            response.text, 9
         )
-        self.assertInSnippet('old snippet', response.body, 52)
+        self.assertInSnippet('old snippet', response.text, 52)
         self.assertInSnippet(
             '<strong>WARNING:</strong> Snippet will go in the "(unknown)"',
-            response.body, 52
+            response.text, 52
         )
 
     def testHiddenUser(self):
@@ -554,20 +582,20 @@ def testHiddenUser(self):
         self.request_fetcher.get(url)
 
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 2)
+        self.assertNumSnippets(response.text, 2)
         response = self.request_fetcher.get('/weekly?week=02-27-2012')
-        self.assertNumSnippets(response.body, 1)    # "no snippet this week"
+        self.assertNumSnippets(response.text, 1)    # "no snippet this week"
 
         url = '/update_settings?u=user@example.com&is_hidden=yes'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/')
         # Hiding doesn't affect the user-snippets page, just the weekly one.
-        self.assertNumSnippets(response.body, 2)
+        self.assertNumSnippets(response.text, 2)
         response = self.request_fetcher.get('/weekly?week=02-27-2012')
-        self.assertNumSnippets(response.body, 0)
+        self.assertNumSnippets(response.text, 0)
         # And it doesn't affect existing snippets, just empty ones.
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
 
     def testNewSnippetUnhides(self):
         url = '/update_snippet?week=02-13-2012&snippet=my+snippet'
@@ -576,15 +604,15 @@ def testNewSnippetUnhides(self):
         url = '/update_settings?u=user@example.com&is_hidden=yes'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 0)
+        self.assertNumSnippets(response.text, 0)
 
         url = '/update_snippet?week=02-27-2012&snippet=new+snippet'
         self.request_fetcher.get(url)
 
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
         response = self.request_fetcher.get('/weekly?week=02-27-2012')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
 
     def testChangingSettingsUnhides(self):
         url = '/update_snippet?week=02-20-2012&snippet=my+snippet'
@@ -593,12 +621,12 @@ def testChangingSettingsUnhides(self):
         url = '/update_settings?u=user@example.com&is_hidden=yes'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-27-2012')
-        self.assertNumSnippets(response.body, 0)
+        self.assertNumSnippets(response.text, 0)
 
         url = '/update_settings?u=user@example.com'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-27-2012')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
 
     def testHideButton(self):
         # First, register the user.
@@ -609,14 +637,14 @@ def testHideButton(self):
         self.request_fetcher.get(url)
 
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
 
         # Now hide using the hide button.
         url = '/update_settings?u=user@example.com&hide=Hide'
         self.request_fetcher.get(url)
 
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 0)
+        self.assertNumSnippets(response.text, 0)
 
     def testDeleteButton(self):
         # First, register the user.
@@ -624,13 +652,13 @@ def testDeleteButton(self):
         self.request_fetcher.get(url)
 
         response = self.request_fetcher.get('/')
-        self.assertNotIn('<title>New user</title>', response.body)
+        self.assertNotIn('<title>New user</title>', response.text)
 
         url = '/update_settings?u=user@example.com&delete=Delete'
         self.request_fetcher.get(url)
 
         response = self.request_fetcher.get('/')
-        self.assertIn('<title>New user</title>', response.body)
+        self.assertIn('<title>New user</title>', response.text)
 
 
 class SetAndViewSnippetsTestCase(UserTestBase):
@@ -640,22 +668,22 @@ def testSetAndViewInUserMode(self):
         url = '/update_snippet?week=02-20-2012&snippet=my+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 2)
-        self.assertInSnippet('>my snippet<', response.body, 0)
+        self.assertNumSnippets(response.text, 2)
+        self.assertInSnippet('>my snippet<', response.text, 0)
 
     def testSetAndViewInWeeklyMode(self):
         url = '/update_snippet?week=02-20-2012&snippet=my+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
-        self.assertInSnippet('>my snippet<', response.body, 0)
+        self.assertNumSnippets(response.text, 1)
+        self.assertInSnippet('>my snippet<', response.text, 0)
 
     def testCannotSeeInOtherWeek(self):
         url = '/update_snippet?week=02-20-2012&snippet=my+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-13-2012')
-        self.assertNumSnippets(response.body, 1)
-        self.assertNotIn('>my snippet<', response.body)
+        self.assertNumSnippets(response.text, 1)
+        self.assertNotIn('>my snippet<', response.text)
 
     def testViewSnippetsForTwoUsers(self):
         url = '/update_snippet?week=02-20-2012&snippet=my+snippet'
@@ -666,32 +694,32 @@ def testViewSnippetsForTwoUsers(self):
 
         # This is done as other
         response = self.request_fetcher.get('/')
-        self.assertIn('other@example.com', response.body)
-        self.assertNumSnippets(response.body, 2)
-        self.assertInSnippet('>other snippet<', response.body, 0)
-        self.assertNotIn('user@example.com', response.body)
-        self.assertNotIn('>my snippet<', response.body)
+        self.assertIn('other@example.com', response.text)
+        self.assertNumSnippets(response.text, 2)
+        self.assertInSnippet('>other snippet<', response.text, 0)
+        self.assertNotIn('user@example.com', response.text)
+        self.assertNotIn('>my snippet<', response.text)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 2)
-        self.assertInSnippet('other@example.com', response.body, 0)
-        self.assertInSnippet('>other snippet<', response.body, 0)
-        self.assertInSnippet('user@example.com', response.body, 1)
-        self.assertInSnippet('>my snippet<', response.body, 1)
+        self.assertNumSnippets(response.text, 2)
+        self.assertInSnippet('other@example.com', response.text, 0)
+        self.assertInSnippet('>other snippet<', response.text, 0)
+        self.assertInSnippet('user@example.com', response.text, 1)
+        self.assertInSnippet('>my snippet<', response.text, 1)
 
         # This is done as user
         self.login('user@example.com')
         response = self.request_fetcher.get('/')
-        self.assertIn('user@example.com', response.body)
-        self.assertNumSnippets(response.body, 2)
-        self.assertInSnippet('>my snippet<', response.body, 0)
-        self.assertNotIn('other@example.com', response.body)
-        self.assertNotIn('>other snippet<', response.body)
+        self.assertIn('user@example.com', response.text)
+        self.assertNumSnippets(response.text, 2)
+        self.assertInSnippet('>my snippet<', response.text, 0)
+        self.assertNotIn('other@example.com', response.text)
+        self.assertNotIn('>other snippet<', response.text)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 2)
-        self.assertInSnippet('other@example.com', response.body, 0)
-        self.assertInSnippet('>other snippet<', response.body, 0)
-        self.assertInSnippet('user@example.com', response.body, 1)
-        self.assertInSnippet('>my snippet<', response.body, 1)
+        self.assertNumSnippets(response.text, 2)
+        self.assertInSnippet('other@example.com', response.text, 0)
+        self.assertInSnippet('>other snippet<', response.text, 0)
+        self.assertInSnippet('user@example.com', response.text, 1)
+        self.assertInSnippet('>my snippet<', response.text, 1)
 
     def testViewSnippetsForTwoWeeks(self):
         url = '/update_snippet?week=02-20-2012&snippet=my+snippet'
@@ -700,27 +728,27 @@ def testViewSnippetsForTwoWeeks(self):
         self.request_fetcher.get(url)
 
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 3)
+        self.assertNumSnippets(response.text, 3)
         # Snippets go in reverse chronological order (i.e. newest first)
-        self.assertInSnippet('>my second snippet<', response.body, 0)
-        self.assertInSnippet('>my snippet<', response.body, 1)
+        self.assertInSnippet('>my second snippet<', response.text, 0)
+        self.assertInSnippet('>my snippet<', response.text, 1)
 
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
-        self.assertInSnippet('user@example.com', response.body, 0)
-        self.assertInSnippet('>my snippet<', response.body, 0)
-        self.assertNotIn('>my second snippet<', response.body)
+        self.assertNumSnippets(response.text, 1)
+        self.assertInSnippet('user@example.com', response.text, 0)
+        self.assertInSnippet('>my snippet<', response.text, 0)
+        self.assertNotIn('>my second snippet<', response.text)
 
         response = self.request_fetcher.get('/weekly?week=02-27-2012')
-        self.assertNumSnippets(response.body, 1)
-        self.assertInSnippet('user@example.com', response.body, 0)
-        self.assertInSnippet('>my second snippet<', response.body, 0)
-        self.assertNotIn('>my snippet<', response.body)
+        self.assertNumSnippets(response.text, 1)
+        self.assertInSnippet('user@example.com', response.text, 0)
+        self.assertInSnippet('>my second snippet<', response.text, 0)
+        self.assertNotIn('>my snippet<', response.text)
 
         response = self.request_fetcher.get('/weekly?week=02-13-2012')
-        self.assertNumSnippets(response.body, 1)
-        self.assertNotIn('>my snippet<', response.body)
-        self.assertNotIn('>my second snippet<', response.body)
+        self.assertNumSnippets(response.text, 1)
+        self.assertNotIn('>my snippet<', response.text)
+        self.assertNotIn('>my second snippet<', response.text)
 
     def testViewEmptySnippetsInWeekMode(self):
         url = '/update_snippet?week=02-20-2012&snippet=my+snippet'
@@ -730,17 +758,17 @@ def testViewEmptySnippetsInWeekMode(self):
         self.request_fetcher.get(url)
 
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 2)
+        self.assertNumSnippets(response.text, 2)
         # Other-user comes first alphabetically.
-        self.assertInSnippet('other@example.com', response.body, 0)
-        self.assertInSnippet('user@example.com', response.body, 1)
-        self.assertInSnippet('>my snippet<', response.body, 1)
+        self.assertInSnippet('other@example.com', response.text, 0)
+        self.assertInSnippet('user@example.com', response.text, 1)
+        self.assertInSnippet('>my snippet<', response.text, 1)
 
         response = self.request_fetcher.get('/weekly?week=02-27-2012')
-        self.assertNumSnippets(response.body, 2)
-        self.assertInSnippet('other@example.com', response.body, 0)
-        self.assertInSnippet('>other snippet<', response.body, 0)
-        self.assertInSnippet('user@example.com', response.body, 1)
+        self.assertNumSnippets(response.text, 2)
+        self.assertInSnippet('other@example.com', response.text, 0)
+        self.assertInSnippet('>other snippet<', response.text, 0)
+        self.assertInSnippet('user@example.com', response.text, 1)
 
     def testViewEmptySnippetsInUserMode(self):
         """Occurs when there's a gap between two snippets."""
@@ -750,9 +778,9 @@ def testViewEmptySnippetsInUserMode(self):
         self.request_fetcher.get(url)
 
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 3)
-        self.assertInSnippet('>my snippet<', response.body, 0)
-        self.assertInSnippet('>my old snippet<', response.body, 2)
+        self.assertNumSnippets(response.text, 3)
+        self.assertInSnippet('>my snippet<', response.text, 0)
+        self.assertInSnippet('>my old snippet<', response.text, 2)
 
     def testCategorizeSnippets(self):
         """Weekly view should sort based on user categories."""
@@ -782,11 +810,11 @@ def testCategorizeSnippets(self):
         # Order should be 4 ((unknown) category), 2 and 3 (a 1st) and
         # then 1 (b 2nd).
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 4)
-        self.assertInSnippet('4@example.com', response.body, 0)
-        self.assertInSnippet('2@example.com', response.body, 1)
-        self.assertInSnippet('3@example.com', response.body, 2)
-        self.assertInSnippet('1@example.com', response.body, 3)
+        self.assertNumSnippets(response.text, 4)
+        self.assertInSnippet('4@example.com', response.text, 0)
+        self.assertInSnippet('2@example.com', response.text, 1)
+        self.assertInSnippet('3@example.com', response.text, 2)
+        self.assertInSnippet('1@example.com', response.text, 3)
 
     def testViewSnippetAfterAUserIsDeleted(self):
         """When a user is deleted, their snippet should still show up."""
@@ -797,146 +825,146 @@ def testViewSnippetAfterAUserIsDeleted(self):
         self.request_fetcher.get(url)
 
         # Now delete user 2
-        u = models.User.all().filter('email =', '2@example.com').get()
-        u.delete()
+        u = models.User.query(models.User.email == '2@example.com').get()
+        u.key.delete()
 
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
-        self.assertInSnippet('2@example.com', response.body, 0)
-        self.assertTrue('(unknown)' in response.body)
+        self.assertNumSnippets(response.text, 1)
+        self.assertInSnippet('2@example.com', response.text, 0)
+        self.assertTrue('(unknown)' in response.text)
 
     def testWarningsWhenDue(self):
         url = '/update_snippet?week=02-06-2012&snippet=old+snippet'
         self.request_fetcher.get(url)
 
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 19)
-        response = self.request_fetcher.get('/')
-        self.assertNotIn('Due today', response.body)
-        self.assertNotIn('OVERDUE', response.body)
+        with time_machine.travel(datetime.datetime(2012, 2, 19)):
+            response = self.request_fetcher.get('/')
+        self.assertNotIn('Due today', response.text)
+        self.assertNotIn('OVERDUE', response.text)
 
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 20)
-        response = self.request_fetcher.get('/')
-        self.assertIn('Due today', response.body)
-        self.assertNotIn('OVERDUE', response.body)
+        with time_machine.travel(datetime.datetime(2012, 2, 20)):
+            response = self.request_fetcher.get('/')
+        self.assertIn('Due today', response.text)
+        self.assertNotIn('OVERDUE', response.text)
 
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 21)
-        response = self.request_fetcher.get('/')
-        self.assertNotIn('Due today', response.body)
-        self.assertIn('OVERDUE', response.body)
+        with time_machine.travel(datetime.datetime(2012, 2, 21)):
+            response = self.request_fetcher.get('/')
+        self.assertNotIn('Due today', response.text)
+        self.assertIn('OVERDUE', response.text)
 
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 22)
-        response = self.request_fetcher.get('/')
-        self.assertNotIn('Due today', response.body)
-        self.assertIn('OVERDUE', response.body)
+        with time_machine.travel(datetime.datetime(2012, 2, 22)):
+            response = self.request_fetcher.get('/')
+        self.assertNotIn('Due today', response.text)
+        self.assertIn('OVERDUE', response.text)
 
     def testWarningsWhenNotDue(self):
         url = '/update_snippet?week=02-13-2012&snippet=my+snippet'
         self.request_fetcher.get(url)
 
         for date in (19, 20, 21, 22):
-            snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, date)
-            response = self.request_fetcher.get('/')
-            self.assertNotIn('Due today', response.body)
-            self.assertNotIn('OVERDUE', response.body)
+            with time_machine.travel(datetime.datetime(2012, 2, date)):
+                response = self.request_fetcher.get('/')
+            self.assertNotIn('Due today', response.text)
+            self.assertNotIn('OVERDUE', response.text)
 
     def testPrettyDateFormatting(self):
         # Just so we're not a new user.
         url = '/update_snippet?week=02-06-2012&snippet=my+snippet'
         self.request_fetcher.get(url)
 
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 6)
-        response = self.request_fetcher.get('/')
-        self.assertIn('February 6, 2012', response.body)
+        with time_machine.travel(datetime.datetime(2012, 2, 6)):
+            response = self.request_fetcher.get('/')
+        self.assertIn('February 6, 2012', response.text)
 
     def testUrlize(self):
         url = '/update_snippet?week=02-20-2012&snippet=visit+http://foo.com'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
-        self.assertInSnippet(
-            '>visit <a href="http://foo.com">http://foo.com</a><',
-            response.body, 0)
+        self.assertNumSnippets(response.text, 1)
+        self.assertSnippetRegex(
+            r'>visit <a href="http://foo.com".*>http://foo.com</a><',
+            response.text, 0)
 
         # Also make sure we urlize on the user page.
         self.login('2@example.com')
         response = self.request_fetcher.get('/?u=user@example.com')
-        self.assertNumSnippets(response.body, 2)
-        self.assertInSnippet(
-            '>visit <a href="http://foo.com">http://foo.com</a><',
-            response.body, 0)
+        self.assertNumSnippets(response.text, 2)
+        self.assertSnippetRegex(
+            r'>visit <a href="http://foo.com".*>http://foo.com</a><',
+            response.text, 0)
 
     def testEditMode(self):
         url = '/update_snippet?week=02-20-2012&snippet=hello'
         self.request_fetcher.get(url)
 
         response = self.request_fetcher.get('/?u=user@example.com')
-        self.assertIn('Make snippet private', response.body)
+        self.assertIn('Make snippet private', response.text)
 
         response = self.request_fetcher.get('/?u=user@example.com&edit=1')
-        self.assertIn('Make snippet private', response.body)
+        self.assertIn('Make snippet private', response.text)
 
         response = self.request_fetcher.get('/?u=user@example.com&edit=0')
-        self.assertNotIn('Make snippet private', response.body)
+        self.assertNotIn('Make snippet private', response.text)
 
 
 class ShowCorrectWeekTestCase(UserTestBase):
     """Test we show the right snippets for edit/view based on day of week."""
 
     def setUp(self):
-        super(ShowCorrectWeekTestCase, self).setUp()
+        super().setUp()
         # Register the user so snippet-fetching works.
         url = '/update_settings?category=dummy'
         self.request_fetcher.get(url)
 
     def testMonday(self):
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 20)
-        response = self.request_fetcher.get('/')
-        self.assertInSnippet('February 20, 2012', response.body, 0)
+        with time_machine.travel(datetime.datetime(2012, 2, 20)):
+            response = self.request_fetcher.get('/')
+        self.assertInSnippet('February 20, 2012', response.text, 0)
         # For *viewing*'s snippets, we always show last week's snippets.
         response = self.request_fetcher.get('/weekly')
-        self.assertIn('February 13, 2012', response.body)
+        self.assertIn('February 13, 2012', response.text)
 
     def testTuesday(self):
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 21)
-        response = self.request_fetcher.get('/')
-        self.assertInSnippet('February 20, 2012', response.body, 0)
+        with time_machine.travel(datetime.datetime(2012, 2, 21)):
+            response = self.request_fetcher.get('/')
+        self.assertInSnippet('February 20, 2012', response.text, 0)
         response = self.request_fetcher.get('/weekly')
-        self.assertIn('February 13, 2012', response.body)
+        self.assertIn('February 13, 2012', response.text)
 
     def testWednesday(self):
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 22)
-        response = self.request_fetcher.get('/')
-        self.assertInSnippet('February 20, 2012', response.body, 0)
+        with time_machine.travel(datetime.datetime(2012, 2, 22)):
+            response = self.request_fetcher.get('/')
+        self.assertInSnippet('February 20, 2012', response.text, 0)
         response = self.request_fetcher.get('/weekly')
-        self.assertIn('February 13, 2012', response.body)
+        self.assertIn('February 13, 2012', response.text)
 
     def testThursday(self):
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 23)
-        response = self.request_fetcher.get('/')
-        self.assertInSnippet('February 20, 2012', response.body, 0)
+        with time_machine.travel(datetime.datetime(2012, 2, 23)):
+            response = self.request_fetcher.get('/')
+        self.assertInSnippet('February 20, 2012', response.text, 0)
         response = self.request_fetcher.get('/weekly')
-        self.assertIn('February 13, 2012', response.body)
+        self.assertIn('February 13, 2012', response.text)
 
     def testFriday(self):
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 24)
-        response = self.request_fetcher.get('/')
-        self.assertInSnippet('February 20, 2012', response.body, 0)
+        with time_machine.travel(datetime.datetime(2012, 2, 24)):
+            response = self.request_fetcher.get('/')
+        self.assertInSnippet('February 20, 2012', response.text, 0)
         response = self.request_fetcher.get('/weekly')
-        self.assertIn('February 13, 2012', response.body)
+        self.assertIn('February 13, 2012', response.text)
 
     def testSaturday(self):
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 25)
-        response = self.request_fetcher.get('/')
-        self.assertInSnippet('February 20, 2012', response.body, 0)
+        with time_machine.travel(datetime.datetime(2012, 2, 25)):
+            response = self.request_fetcher.get('/')
+        self.assertInSnippet('February 20, 2012', response.text, 0)
         response = self.request_fetcher.get('/weekly')
-        self.assertIn('February 13, 2012', response.body)
+        self.assertIn('February 13, 2012', response.text)
 
     def testSunday(self):
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 26)
-        response = self.request_fetcher.get('/')
-        self.assertInSnippet('February 20, 2012', response.body, 0)
+        with time_machine.travel(datetime.datetime(2012, 2, 26)):
+            response = self.request_fetcher.get('/')
+        self.assertInSnippet('February 20, 2012', response.text, 0)
         response = self.request_fetcher.get('/weekly')
-        self.assertIn('February 13, 2012', response.body)
+        self.assertIn('February 13, 2012', response.text)
 
 
 class NosnippetGapFillingTestCase(UserTestBase):
@@ -945,23 +973,23 @@ class NosnippetGapFillingTestCase(UserTestBase):
     def testNoSnippets(self):
         # If nobody is registered, the user-db will be empty.
         response = self.request_fetcher.get('/weekly')
-        self.assertNumSnippets(response.body, 0)
+        self.assertNumSnippets(response.text, 0)
 
         url = '/update_settings?category=dummy'   # register the user
         self.request_fetcher.get(url)
 
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 2)
+        self.assertNumSnippets(response.text, 2)
 
     def testOneSnippetInDistantPast(self):
         url = '/update_snippet?week=02-21-2011&snippet=old+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 53)
-        self.assertInSnippet('old snippet', response.body, 52)
+        self.assertNumSnippets(response.text, 53)
+        self.assertInSnippet('old snippet', response.text, 52)
 
         response = self.request_fetcher.get('/weekly')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
 
     def testTwoSnippetsInDistantPast(self):
         url = '/update_snippet?week=08-22-2011&snippet=oldish+snippet'
@@ -969,22 +997,22 @@ def testTwoSnippetsInDistantPast(self):
         url = '/update_snippet?week=02-21-2011&snippet=old+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 53)
-        self.assertInSnippet('oldish snippet', response.body, 26)
-        self.assertInSnippet('old snippet', response.body, 52)
+        self.assertNumSnippets(response.text, 53)
+        self.assertInSnippet('oldish snippet', response.text, 26)
+        self.assertInSnippet('old snippet', response.text, 52)
 
         response = self.request_fetcher.get('/weekly')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
 
     def testSnippetInTheFuture(self):
         url = '/update_snippet?week=02-18-2013&snippet=future+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 54)
-        self.assertInSnippet('future snippet', response.body, 0)
+        self.assertNumSnippets(response.text, 54)
+        self.assertInSnippet('future snippet', response.text, 0)
 
         response = self.request_fetcher.get('/weekly')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
 
     def testSnippetInThePastAndFuture(self):
         url = '/update_snippet?week=02-21-2011&snippet=old+snippet'
@@ -992,19 +1020,19 @@ def testSnippetInThePastAndFuture(self):
         url = '/update_snippet?week=02-18-2013&snippet=future+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/')
-        self.assertNumSnippets(response.body, 105)
-        self.assertInSnippet('future snippet', response.body, 0)
-        self.assertInSnippet('old snippet', response.body, 104)
+        self.assertNumSnippets(response.text, 105)
+        self.assertInSnippet('future snippet', response.text, 0)
+        self.assertInSnippet('old snippet', response.text, 104)
 
         response = self.request_fetcher.get('/weekly')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
 
 
 class PrivateSnippetTestCase(UserTestBase):
     """Tests that we properly restrict viewing of private snippets."""
 
     def setUp(self):
-        super(PrivateSnippetTestCase, self).setUp()
+        super().setUp()
         # Set up a user with some private and some not-private snippets,
         # another user with only private, and another with only public.
         self.login('private@example.com')
@@ -1036,51 +1064,51 @@ def setUp(self):
     def testAdminCanSeeAllSnippets(self):
         self.set_is_admin()
         response = self.request_fetcher.get('/weekly?week=02-13-2012')
-        self.assertNumSnippets(response.body, 4)
+        self.assertNumSnippets(response.text, 4)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 4)
+        self.assertNumSnippets(response.text, 4)
 
     def testUserCanSeeAllSnippetsFromTheirDomain(self):
         # As user@example.com, we can see all but some_other_domain.com
         response = self.request_fetcher.get('/weekly?week=02-13-2012')
         # For private@some_other_domain.com, we should see 'no snippet found'.
-        self.assertNumSnippets(response.body, 4)
-        self.assertInSnippet('private@some_other_domain.com', response.body, 2)
-        self.assertNotInSnippet('foreign', response.body, 2)
+        self.assertNumSnippets(response.text, 4)
+        self.assertInSnippet('private@some_other_domain.com', response.text, 2)
+        self.assertNotInSnippet('foreign', response.text, 2)
         # We *should* see stuff from our domain, but marked private.
-        self.assertInSnippet('private@example.com', response.body, 1)
-        self.assertInSnippet('snippet-tag-private', response.body, 1)
-        self.assertInSnippet('no see um', response.body, 1)
+        self.assertInSnippet('private@example.com', response.text, 1)
+        self.assertInSnippet('snippet-tag-private', response.text, 1)
+        self.assertInSnippet('no see um', response.text, 1)
         # And we should see public snippets, not marked private.
-        self.assertInSnippet('public@example.com', response.body, 3)
-        self.assertNotInSnippet('snippet-tag-private', response.body, 3)
-        self.assertInSnippet('see me', response.body, 3)
+        self.assertInSnippet('public@example.com', response.text, 3)
+        self.assertNotInSnippet('snippet-tag-private', response.text, 3)
+        self.assertInSnippet('see me', response.text, 3)
 
         self.login('random@some_other_domain.com')
         response = self.request_fetcher.get('/weekly?week=02-13-2012')
-        self.assertNumSnippets(response.body, 4)
-        self.assertInSnippet('private@some_other_domain.com', response.body, 2)
-        self.assertInSnippet('foreign', response.body, 2)
-        self.assertInSnippet('snippet-tag-private', response.body, 2)
+        self.assertNumSnippets(response.text, 4)
+        self.assertInSnippet('private@some_other_domain.com', response.text, 2)
+        self.assertInSnippet('foreign', response.text, 2)
+        self.assertInSnippet('snippet-tag-private', response.text, 2)
         # Now we shouldn't see stuff from example.com
-        self.assertInSnippet('private@example.com', response.body, 1)
-        self.assertNotInSnippet('no see um', response.body, 1)
+        self.assertInSnippet('private@example.com', response.text, 1)
+        self.assertNotInSnippet('no see um', response.text, 1)
         # And we should also see public snippets, not in gray.
-        self.assertInSnippet('public@example.com', response.body, 3)
-        self.assertNotInSnippet('snippet-tag-private', response.body, 3)
-        self.assertInSnippet('see me', response.body, 3)
+        self.assertInSnippet('public@example.com', response.text, 3)
+        self.assertNotInSnippet('snippet-tag-private', response.text, 3)
+        self.assertInSnippet('see me', response.text, 3)
 
     def testPrivacyIsPerSnippet(self):
         self.login('random@some_other_domain.com')
         response = self.request_fetcher.get('/weekly?week=02-13-2012')
-        self.assertNumSnippets(response.body, 4)
-        self.assertInSnippet('mixed@example.com', response.body, 0)
-        self.assertNotInSnippet('cautious', response.body, 0)
+        self.assertNumSnippets(response.text, 4)
+        self.assertInSnippet('mixed@example.com', response.text, 0)
+        self.assertNotInSnippet('cautious', response.text, 0)
 
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 4)
-        self.assertInSnippet('mixed@example.com', response.body, 0)
-        self.assertInSnippet('not cautious', response.body, 0)
+        self.assertNumSnippets(response.text, 4)
+        self.assertInSnippet('mixed@example.com', response.text, 0)
+        self.assertInSnippet('not cautious', response.text, 0)
 
     def testDomainMatching(self):
         # Let's make it legal for all these domains to log in.
@@ -1107,10 +1135,10 @@ def testDomainMatching(self):
 
         self.login('user@example.com')
         response = self.request_fetcher.get('/weekly?week=02-13-2012')
-        self.assertNumSnippets(response.body, 8)
+        self.assertNumSnippets(response.text, 8)
         for i in (0, 1, 2, 3):    # the 4 close@ snippets should sort first
-            self.assertInSnippet('close@', response.body, i)
-            self.assertNotInSnippet('whoa', response.body, i)
+            self.assertInSnippet('close@', response.text, i)
+            self.assertNotInSnippet('whoa', response.text, i)
 
 
 class MarkdownSnippetTestCase(UserTestBase):
@@ -1121,7 +1149,7 @@ class MarkdownSnippetTestCase(UserTestBase):
     class.
     """
     def setUp(self):
-        super(MarkdownSnippetTestCase, self).setUp()
+        super().setUp()
 
         # Set up some snippets as markdown, and some not.
         url = ('/update_snippet?week=02-13-2012&snippet=*+item+1%0A*+item+2'
@@ -1132,35 +1160,35 @@ def setUp(self):
 
     def testMarkdownRendering(self):
         response = self.request_fetcher.get('/weekly?week=02-13-2012')
-        self.assertInSnippet('class="snippet-text-markdown', response.body, 0)
+        self.assertInSnippet('class="snippet-text-markdown', response.text, 0)
 
     def testTextRendering(self):
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertInSnippet('class="snippet-text', response.body, 0)
+        self.assertInSnippet('class="snippet-text', response.text, 0)
 
 
 class ManageUsersTestCase(UserTestBase):
     """Test we can delete users properly."""
     def setUp(self):
-        super(ManageUsersTestCase, self).setUp()
+        super().setUp()
 
         # Have users with various snippet characteristics.
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 20, 12, 0, 0)
-        self.login('has_one_snippet@example.com')
-        self.request_fetcher.get('/update_snippet?week=02-13-2012&snippet=s1')
+        with time_machine.travel(datetime.datetime(2012, 2, 20, 12, 0, 0)):
+            self.login('has_one_snippet@example.com')
+            self.request_fetcher.get('/update_snippet?week=02-13-2012&snippet=s1')
 
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 20, 12, 0, 1)
-        self.login('has_many_snippets@example.com')
-        self.request_fetcher.get('/update_snippet?week=01-30-2012&snippet=s2')
-        self.request_fetcher.get('/update_snippet?week=02-13-2012&snippet=s3')
+        with time_machine.travel(datetime.datetime(2012, 2, 20, 12, 0, 1)):
+            self.login('has_many_snippets@example.com')
+            self.request_fetcher.get('/update_snippet?week=01-30-2012&snippet=s2')
+            self.request_fetcher.get('/update_snippet?week=02-13-2012&snippet=s3')
 
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 20, 12, 0, 2)
-        self.login('has_old_snippet@example.com')
-        self.request_fetcher.get('/update_snippet?week=02-14-2011&snippet=s4')
+        with time_machine.travel(datetime.datetime(2012, 2, 20, 12, 0, 2)):
+            self.login('has_old_snippet@example.com')
+            self.request_fetcher.get('/update_snippet?week=02-14-2011&snippet=s4')
 
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 20, 12, 0, 3)
-        self.login('has_no_snippets@example.com')
-        self.request_fetcher.get('/update_settings')
+        with time_machine.travel(datetime.datetime(2012, 2, 20, 12, 0, 3)):
+            self.login('has_no_snippets@example.com')
+            self.request_fetcher.get('/update_settings')
 
     def get_user_list(self, body):
         """Returns the email usernames of the user-list, in order."""
@@ -1175,8 +1203,8 @@ def testSortByEmail(self):
                                             '?sort_by=email')
         expected = ['has_many_snippets', 'has_no_snippets',
                     'has_old_snippet', 'has_one_snippet']
-        self.assertEqual(expected, self.get_user_list(response.body))
-        self.assertNotIn('@example.com deleted', response.body)  # we didn't
+        self.assertEqual(expected, self.get_user_list(response.text))
+        self.assertNotIn('@example.com deleted', response.text)  # we didn't
 
     def testSortByCreation(self):
         response = self.request_fetcher.get('/admin/manage_users'
@@ -1184,8 +1212,8 @@ def testSortByCreation(self):
         # Reverse order from when we created them above.
         expected = ['has_no_snippets', 'has_old_snippet',
                     'has_many_snippets', 'has_one_snippet']
-        self.assertEqual(expected, self.get_user_list(response.body))
-        self.assertNotIn('@example.com deleted', response.body)  # we didn't
+        self.assertEqual(expected, self.get_user_list(response.text))
+        self.assertNotIn('@example.com deleted', response.text)  # we didn't
 
     def testSortByLastSnippet(self):
         response = self.request_fetcher.get('/admin/manage_users'
@@ -1193,78 +1221,114 @@ def testSortByLastSnippet(self):
         # 'many' and 'one' are tied; the tiebreak is email.
         expected = ['has_no_snippets', 'has_old_snippet',
                     'has_many_snippets', 'has_one_snippet']
-        self.assertEqual(expected, self.get_user_list(response.body))
-        self.assertNotIn('@example.com deleted', response.body)  # we didn't
+        self.assertEqual(expected, self.get_user_list(response.text))
+        self.assertNotIn('@example.com deleted', response.text)  # we didn't
 
     def testBadSortBy(self):
         # status=500 means we expect to get back a 500 error for this.
-        self.request_fetcher.get('/admin/manage_users?sort_by=unknown',
-                                 status=500)
+        response = self.request_fetcher.get('/admin/manage_users?sort_by=unknown')
+        self.assertEqual(response.status_code, 500)
 
     def testDelete(self):
-        response = self.request_fetcher.get(
-            '/admin/manage_users?delete+has_old_snippet@example.com=Delete')
-        if response.status_int in (301, 302, 303, 304):
-            response = response.follow()
+        response = self.request_fetcher.post(
+            '/admin/manage_users',
+            data={
+                "action": "delete",
+                "email": "has_old_snippet@example.com",
+            },
+            follow_redirects=True)
 
         expected = ['has_no_snippets', 'has_many_snippets', 'has_one_snippet']
-        self.assertEqual(expected, self.get_user_list(response.body))
-        self.assertIn('has_old_snippet@example.com deleted', response.body)
+        self.assertEqual(expected, self.get_user_list(response.text))
+        self.assertIn('has_old_snippet@example.com deleted', response.text)
 
     def testHide(self):
-        response = self.request_fetcher.get(
-            '/admin/manage_users?hide+has_old_snippet@example.com=Hide')
-        if response.status_int in (301, 302, 303, 304):
-            response = response.follow()
+        response = self.request_fetcher.post(
+            '/admin/manage_users',
+            data={
+                "action": "hide",
+                "email": "has_old_snippet@example.com",
+            },
+            follow_redirects=True)
 
         expected = ['has_no_snippets', 'has_old_snippet',
                     'has_many_snippets', 'has_one_snippet']
-        self.assertEqual(expected, self.get_user_list(response.body))
-        self.assertIn('has_old_snippet@example.com hidden', response.body)
-        self.assertIn('value="Unhide"', response.body)
+        self.assertEqual(expected, self.get_user_list(response.text))
+        self.assertIn('has_old_snippet@example.com hidden', response.text)
+        self.assertIn('value="Unhide"', response.text)
 
     def testPreserveSortBy(self):
         response = self.request_fetcher.get(
             '/admin/manage_users?hide+has_old_snippet@example.com=Hide'
-            '&sort_by=last_snippet_time')
-        if response.status_int in (301, 302, 303, 304):
-            response = response.follow()
+            '&sort_by=last_snippet_time',
+            follow_redirects=True)
 
         # "Last snippet" shouldn't have a link letting you sort by
         # last snippet, because it should already be doing so!
-        self.assertIn('<th>Last snippet</th>', response.body)
+        self.assertIn('<th>Last snippet</th>', response.text)
 
     def testUnhide(self):
-        self.request_fetcher.get(
-            '/admin/manage_users?hide+has_old_snippet@example.com=Hide')
-        response = self.request_fetcher.get(
-            '/admin/manage_users?unhide+has_old_snippet@example.com=Hide')
-        if response.status_int in (301, 302, 303, 304):
-            response = response.follow()
+        self.request_fetcher.post(
+            '/admin/manage_users',
+            data={
+                "action": "hide",
+                "email": "has_old_snippet@example.com",
+            })
+        response = self.request_fetcher.post(
+            '/admin/manage_users',
+            data={
+                "action": "unhide",
+                "email": "has_old_snippet@example.com",
+            },
+            follow_redirects=True)
 
         expected = ['has_no_snippets', 'has_old_snippet',
                     'has_many_snippets', 'has_one_snippet']
-        self.assertEqual(expected, self.get_user_list(response.body))
-        self.assertIn('has_old_snippet@example.com unhidden', response.body)
-        self.assertNotIn('value="Unhide"', response.body)
+        self.assertEqual(expected, self.get_user_list(response.text))
+        self.assertIn('has_old_snippet@example.com unhidden', response.text)
+        self.assertNotIn('value="Unhide"', response.text)
 
     def testInvalidButton(self):
-        self.request_fetcher.get('/admin/manage_users'
-                                 '?delete+has_old_snippet=Delete',
-                                 status=500)
-        self.request_fetcher.get('/admin/manage_users'
-                                 '?hide+has_old_snippet=Hide',
-                                 status=500)
-        self.request_fetcher.get('/admin/manage_users'
-                                 '?unhide+has_old_snippet=Unhide',
-                                 status=500)
+        self.assertEqual(
+            self.request_fetcher.post(
+                '/admin/manage_users',
+                data={
+                    "action": "delete",
+                    "email": "has_old_snippet",
+                }
+            ).status_code,
+            500
+        )
+        self.assertEqual(
+            self.request_fetcher.post(
+                '/admin/manage_users',
+                data={
+                    "action": "hide",
+                    "email": "has_old_snippet",
+                }
+            ).status_code,
+            500
+        )
+        self.assertEqual(
+            self.request_fetcher.post(
+                '/admin/manage_users',
+                data={
+                    "action": "unhide",
+                    "email": "has_old_snippet",
+                }
+            ).status_code,
+            500
+        )
 
 
+# We send out mail on Sunday nights and Monday mornings, so we'll set 'today' to
+# be Sunday right around midnight.
+@time_machine.travel(datetime.datetime(2012, 2, 19, 23, 50, 0, tzinfo=ZoneInfo("UTC")))
 class SendingEmailTestCase(UserTestBase):
     """Test we correctly send cron emails."""
 
     def setUp(self):
-        super(SendingEmailTestCase, self).setUp()
+        super().setUp()
         self.testbed.init_mail_stub()
         self.mail_stub = self.testbed.get_stub(testbed.MAIL_SERVICE_NAME)
         # The email-senders sleep 2 seconds between sends for quota
@@ -1273,10 +1337,6 @@ def setUp(self):
         self.sleep_fn = time.sleep
         time.sleep = lambda sec: sec
 
-        # We send out mail on Sunday nights and Monday mornings, so
-        # we'll set 'today' to be Sunday right around midnight.
-        snippets._TODAY_FN = lambda: datetime.datetime(2012, 2, 19, 23, 50, 0)
-
         # For our mail tests, we set up a db with a few users, some of
         # whom have snippets for this week ('this week' being 13 Feb
         # 2012), some of whom don't.
@@ -1296,8 +1356,8 @@ def setUp(self):
         self.login('user@example.com')        # back to the normal user
 
     def tearDown(self):
-        UserTestBase.tearDown(self)
         time.sleep = self.sleep_fn
+        super().tearDown()
 
     def assertEmailSentTo(self, email):
         r = self.mail_stub.get_sent_messages(to=email)
@@ -1323,7 +1383,7 @@ def testMustBeAdminToSendMail(self):
 
     def testDoNotSendMailWithoutSetting(self):
         app_settings = models.AppSettings.get()
-        app_settings.delete()
+        app_settings.key.delete()
         self.request_fetcher.get('/admin/send_reminder_email')
         self.assertEmailNotSentTo('does_not_have_snippet@example.com')
 
@@ -1411,8 +1471,8 @@ def count_calls_per_minute(sleep_seconds):
         # We'll do 500 users.  Rather than go through the request
         # API, we modify the db directly; it's much faster.
         users = [models.User(email='snippets%d@example.com' % i)
-                 for i in xrange(500)]
-        db.put(users)
+                 for i in range(500)]
+        ndb.put_multi(users)
 
         self.request_fetcher.get('/admin/send_view_email')
         # https://developers.google.com/appengine/docs/quotas#Mail
@@ -1428,7 +1488,7 @@ class SendingChatTestCase(UserTestBase):
     """Test we correctly send to Slack."""
     def setUp(self):
         # (The superclass sets up slack_sends for us.)
-        super(SendingChatTestCase, self).setUp()
+        super().setUp()
         # Let's set up default chat configs.
         app_settings = models.AppSettings.get()
         app_settings.slack_channel = '#slack_chann3l'
@@ -1474,15 +1534,15 @@ def testTrimTrailingSpaces(self):
 class DisplayNameTestCase(UserTestBase):
     """Manipulate a user's display name and check it in weekly page."""
     def setUp(self):
-        super(UserTestBase, self).setUp()
+        super().setUp()
         self.login('user@example.com')
 
     def testUserHasEmptyDisplayName(self):
         url = '/update_snippet?week=02-20-2012&snippet=my+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
-        self.assertInSnippet('<h3>user@example.com:</h3>', response.body, 0)
+        self.assertNumSnippets(response.text, 1)
+        self.assertInSnippet('<h3>user@example.com:</h3>', response.text, 0)
 
     def testUserHasDisplayName(self):
         self.request_fetcher.get(
@@ -1490,9 +1550,9 @@ def testUserHasDisplayName(self):
         url = '/update_snippet?week=02-20-2012&snippet=my+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
         self.assertInSnippet('<h3>test name (user@example.com):</h3>',
-                             response.body, 0)
+                             response.text, 0)
 
     def testUserChangesDisplayName(self):
         self.request_fetcher.get(
@@ -1500,16 +1560,16 @@ def testUserChangesDisplayName(self):
         url = '/update_snippet?week=02-20-2012&snippet=my+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
         self.assertInSnippet('<h3>test name (user@example.com):</h3>',
-                             response.body, 0)
+                             response.text, 0)
 
         self.request_fetcher.get(
             '/update_settings?u=user@example.com&display_name=fancy+name')
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
         self.assertInSnippet('<h3>fancy name (user@example.com):</h3>',
-                             response.body, 0)
+                             response.text, 0)
 
     def testSnippetHasDisplayName(self):
         self.request_fetcher.get(
@@ -1519,29 +1579,29 @@ def testSnippetHasDisplayName(self):
         self.request_fetcher.get(
             '/update_settings?u=user@example.com&display_name=')
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
         self.assertInSnippet('<h3>test name (user@example.com):</h3>',
-                             response.body, 0)
+                             response.text, 0)
 
     def testSnippetFromDeletedUser(self):
         url = '/update_snippet?week=02-20-2012&snippet=my+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
-        self.assertInSnippet('<h3>user@example.com:</h3>', response.body, 0)
+        self.assertNumSnippets(response.text, 1)
+        self.assertInSnippet('<h3>user@example.com:</h3>', response.text, 0)
 
         self.request_fetcher.get(
             '/update_settings?u=user@example.com&display_name=test+name')
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
         self.assertInSnippet('<h3>test name (user@example.com):</h3>',
-                             response.body, 0)
+                             response.text, 0)
 
         url = '/update_settings?u=user@example.com&delete=Delete'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
-        self.assertInSnippet('<h3>user@example.com:</h3>', response.body, 0)
+        self.assertNumSnippets(response.text, 1)
+        self.assertInSnippet('<h3>user@example.com:</h3>', response.text, 0)
 
     def testSnippetFromDeletedUser2(self):
         self.request_fetcher.get(
@@ -1549,16 +1609,13 @@ def testSnippetFromDeletedUser2(self):
         url = '/update_snippet?week=02-20-2012&snippet=my+snippet'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
         self.assertInSnippet('<h3>test name (user@example.com):</h3>',
-                             response.body, 0)
+                             response.text, 0)
 
         url = '/update_settings?u=user@example.com&delete=Delete'
         self.request_fetcher.get(url)
         response = self.request_fetcher.get('/weekly?week=02-20-2012')
-        self.assertNumSnippets(response.body, 1)
+        self.assertNumSnippets(response.text, 1)
         self.assertInSnippet('<h3>test name (user@example.com):</h3>',
-                             response.body, 0)
-
-if __name__ == '__main__':
-    unittest.main()
+                             response.text, 0)
diff --git a/static/manage_users.js b/static/manage_users.js
index 540d8a8..338168f 100644
--- a/static/manage_users.js
+++ b/static/manage_users.js
@@ -8,7 +8,7 @@ $(function() {
         if ($inputButton.value === "Hide") {
             $inputButton.value = "Hiding...";
             $inputButton.disabled = true;
-            $.ajax("/admin/manage_users?hide%20" + email)
+            $.post("/admin/manage_users", {action: "hide", email: email})
                 .then(function() {
                     $inputButton.name = "unhide " + email;
                     $inputButton.value = "Unhide";
@@ -20,7 +20,7 @@ $(function() {
         } else {
             $inputButton.value = "Unhiding...";
             $inputButton.disabled = true;
-            $.ajax("/admin/manage_users?unhide%20" + email)
+            $.post("/admin/manage_users", {action: "unhide", email: email})
                 .then(function() {
                     $inputButton.name = "hide " + email;
                     $inputButton.value = "Hide";
@@ -37,7 +37,7 @@ $(function() {
         var email = $($inputButton).attr("data-email");
         $inputButton.value = "Deleting...";
         $inputButton.disabled = true;
-        $.ajax("/admin/manage_users?delete%20" + email)
+        $.post("/admin/manage_users", {action: "delete", email: email})
             .then(function() {
                 $inputButton.value = "Deleted";
                 // TODO(csilvers): change the whole row to indicate deleted
diff --git a/templates/app_settings.html b/templates/app_settings.html
index 67bbbc4..ef5075c 100644
--- a/templates/app_settings.html
+++ b/templates/app_settings.html
@@ -9,7 +9,7 @@ <h1>Manage Users</h1>
   hide users</a></p>
 
 
-<form action="/admin/update_settings" method="get" class="user-settings">
+<form action="/admin/update_settings" method="post" class="user-settings">
 
 <h1>Application settings</h1>
 
diff --git a/templates/manage_users.html b/templates/manage_users.html
index 0ae0488..cdbe7fb 100644
--- a/templates/manage_users.html
+++ b/templates/manage_users.html
@@ -10,7 +10,7 @@
   retain their old snippets.)
 </p>
 
-<form action="/admin/manage_users" method="get">
+<form action="/admin/manage_users" method="post">
 <input type="hidden" name="sort_by" value="{{sort_by}}">
 <table>
 <tbody>
diff --git a/templates/settings.html b/templates/settings.html
index 00a7729..d6a26f0 100644
--- a/templates/settings.html
+++ b/templates/settings.html
@@ -27,6 +27,11 @@ <h1>User settings for {{username}}</h1>
   <input id="category" type="text" name="category" value="{{user.category}}">
 </div>
 
+<div class="user-settings-block">
+  <label class="user-settings-label" for="slack-id">Slack User ID</label>
+  <input id="slack-id" type="text" name="slack_id" value="{{user.slack_id}}">
+</div>
+
 <fieldset class="user-settings-block">
   <legend class="user-settings-label">
     Interpret snippets as <a href="http://daringfireball.net/projects/markdown/syntax">markdown</a> by default?
diff --git a/util.py b/util.py
index 8315e96..d5a80c5 100644
--- a/util.py
+++ b/util.py
@@ -3,16 +3,13 @@
 from models import Snippet
 from models import User
 
-
 # Functions for retrieving a user
-def get_user(email):
+def get_user(email: str) -> User | None:
     """Return the user object with the given email, or None if not found."""
-    q = User.all()
-    q.filter('email = ', email)
-    return q.get()
+    return User.query(User.email == email).get()
 
 
-def get_user_or_die(email):
+def get_user_or_die(email: str) -> User:
     user = get_user(email)
     if not user:
         raise ValueError('User "%s" not found' % email)
@@ -21,22 +18,24 @@ def get_user_or_die(email):
 
 def snippets_for_user(user_email):
     """Return all snippets for a given user, oldest snippet first."""
-    snippets_q = Snippet.all()
-    snippets_q.filter('email = ', user_email)
-    snippets_q.order('week')            # this puts oldest snippet first
-    return snippets_q.fetch(1000)       # good for many years...
+    return (
+        Snippet.query(User.email == user_email)
+               .order('week')           # this puts oldest snippet first
+               .fetch(1000)             # good for many years...
+    )
 
 
 def most_recent_snippet_for_user(user_email):
     """Return the most recent snippet for a given user, or None."""
-    snippets_q = Snippet.all()
-    snippets_q.filter('email = ', user_email)
-    snippets_q.order('-week')            # this puts newest snippet first
-    return snippets_q.get()
+    return (
+        Snippet.query(User.email == user_email)
+               .order('-week')          # this puts newest snippet first
+               .get()
+    )
 
 
 # Functions around filling in snippets
-def newsnippet_monday(today):
+def newsnippet_monday(today: datetime.datetime) -> datetime.date:
     """Return a datetime.date object: the monday for new snippets.
 
     We just return the monday for this week.  Saturday and Sunday
@@ -62,7 +61,7 @@ def newsnippet_monday(today):
     return end_monday.date()
 
 
-def existingsnippet_monday(today):
+def existingsnippet_monday(today: datetime.datetime) -> datetime.date:
     """Return a datetime.date object: the monday for existing snippets.
 
     The rule is that we show the snippets for the previous week.  We