casty

Run a real Chrome browser inside your terminal.

Japanese

casty is not a text-mode browser like w3m or lynx. It launches headless Chrome, grabs the rendered frames over CDP, and draws them in your terminal via Kitty graphics protocol. Think of it as a remote desktop for Chrome that fits in a terminal window.

demo.mp4

How It Works

Terminal (you)          casty               Chrome (headless)
┌──────────────┐      ┌──────────────┐      ┌──────────────┐
│  Kitty       │ ←──  │  Screencast  │ ←──  │  Full web    │
│  graphics    │      │  + hi-res    │      │  rendering   │
│  display     │      │  capture     │      │  JS, CSS,    │
│              │ ──→  │  Input       │ ──→  │  Canvas,     │
│  Mouse/KB    │      │  bridge      │      │  WebGL       │
└──────────────┘      └──────────────┘      └──────────────┘

Chrome does all the rendering. casty is just a bridge (~2300 lines) that streams frames to your terminal and sends input back. No Playwright, no puppeteer — raw CDP over WebSocket.

Since it's real Chrome, JavaScript, CSS, Canvas, and WebGL all work. Google login works too (stealth patches bypass bot detection). Mouse clicks, scrolling, dragging, typing — everything you'd expect.

Why use this?

If you're working over SSH on a headless server and need to check a web page, your options are usually curl, lynx, or forwarding X11. casty gives you an actual browser without leaving the terminal. No X11, no VNC, no Wayland — just a Kitty-compatible terminal.

Google Meet with camera & mic (experimental)

Camera and microphone can be streamed to WebRTC sites like Google Meet, Zoom, etc. via ffmpeg. Requires ffmpeg installed. Background effects are not available since the video is captured directly from the device. See Configuration to enable.

Installation

npm install -g @sanohiro/casty
casty

Or from source:

git clone https://github.com/sanohiro/casty.git
cd casty && npm install
./bin/casty

Chrome Headless Shell is auto-installed to ~/.casty/browsers/ on first run.

To use an existing standalone headless shell, select its executable explicitly:

casty --headless-shell /usr/bin/chromium-headless-shell https://example.com

You can also set "headlessShellPath": "/usr/bin/chromium-headless-shell" in ~/.casty/config.json. The command-line option overrides the config. An explicit path skips managed downloads and update checks; an invalid path reports an error. Without a path, casty uses its managed headless shell and does not select a system Chrome/Chromium automatically. External executables must be standalone headless shells, not full desktop browsers.

On a minimal Debian installation, the optional external shell and fonts can be installed with apt install chromium-headless-shell ca-certificates fonts-noto-cjk fonts-noto-color-emoji. Then select /usr/bin/chromium-headless-shell as above.

Requirements

• A terminal with Kitty graphics protocol support (tested on Ghostty, kitty, bcon)
• Node.js >= 18
• unzip (for Chrome auto-install)

tmux

If you run casty inside tmux, enable passthrough so Kitty graphics escape sequences can reach your terminal:

set -g allow-passthrough on

Usage

casty https://google.com
casty https://youtube.com
casty   # opens home page

Keybindings

Key	Action
Alt+L	Address bar
Alt+F	Hint mode (Vimium-style)
Alt+Left / Right	Back / Forward
Alt+C	Copy selected text
Ctrl+V	Paste
Ctrl+Q	Quit

Customizable via ~/.casty/keys.json.

Hint Mode

Alt+F shows labels on clickable elements. Type the label to click. Labels use home-row keys (a s d f j k l).

Address Bar

Alt+L to open. Type a URL or search query. /b query searches bookmarks.

Bookmarks

Create ~/.casty/bookmarks.json:

{
  "GitHub": "https://github.com",
  "YouTube": "https://youtube.com"
}

Configuration

~/.casty/config.json:

{
  "homeUrl": "https://github.com/sanohiro/casty",
  "searchUrl": "https://www.google.com/search?q=",
  "transport": "auto",
  "format": "auto"
}

Key	Description	Default
homeUrl	Start page	https://github.com/sanohiro/casty
headlessShellPath	Explicit path to an external standalone headless shell	Empty (managed download)
searchUrl	Search engine URL	https://www.google.com/search?q=
transport	Image transfer: auto, file, inline	auto (bcon/kitty→file, others→inline)
format	Capture format: auto, png, jpeg (JPEG requires bcon file transfer; otherwise PNG)	auto (bcon file→jpeg adaptive, others→png)
mouseMode	1002 (button-event) or 1003 (any-event)	1003 (hover enabled)
media	Enable camera/mic for WebRTC (experimental, requires ffmpeg)	false

Ghostty uses pixel-level mouse coordinates for precise hover and clicks. Inside tmux, casty uses cell coordinates.

Comparison

	casty	Browsh	w3m/lynx
Engine	Chrome	Firefox	Custom parser
Rendering	Pixel-perfect	Text approximation	Text only
JavaScript	Yes	Yes	No
Display	Kitty graphics	Character cells	Character cells
Dependencies	Node.js + Chrome	Go + Firefox	Standalone

Technical Details

The whole thing is about 1200 lines of JavaScript. Here's what's going on under the hood:

• Launches chrome-headless-shell and talks to it via raw CDP WebSocket
• Runtime.enable is never sent (it breaks Google login — discovered the hard way)
• Stealth patches are injected via Page.addScriptToEvaluateOnNewDocument before any page loads
• Frame capture is hybrid: low-res Screencast triggers change detection, then Page.captureScreenshot grabs hi-res frames with proper DPR
• bcon file transfer uses adaptive JPEG→PNG: fast JPEG during scrolling/video, crisp PNG after things settle
• Terminal pixel size is detected via CSI 14t for auto-zoom

bin/casty          Shell wrapper (Chrome install/update)
bin/casty.js       Entry point (terminal, zoom, resize)
lib/browser.js     CDP browser control, frame capture
lib/cdp.js         Lightweight CDP WebSocket client
lib/chrome.js      Chrome detection, launch, profile cleanup
lib/kitty.js       Kitty graphics protocol (file/inline)
lib/input.js       Mouse/keyboard handling
lib/hints.js       Vimium-style hint mode
lib/urlbar.js      Address/search bar
lib/config.js      User configuration
lib/keys.js        Keybinding config
lib/bookmarks.js   Bookmark search

Troubleshooting

Videos fail to load on ARM64 Linux

Codec support depends on the headless-shell build. Some ARM64 Linux builds do not support H.264 video or AAC audio, even when AV1/VP9 video and Opus audio work. A video that fails to load or reports a duration of zero can be affected by this limitation. Changing the terminal's image transfer format does not add codecs.

To inspect playback from a source checkout, keep casty open on the affected page and run this in another terminal as the same user:

node scripts/diagnose-playback.mjs

The script records the browser version, codec support, media errors, playback state, and Linux audio output information in .local-logs/playback-*.json. It observes the existing session without navigating the page.

No audio on YouTube (Ubuntu Server)

Chrome plays audio directly through the system audio server. If there's no sound:

sudo apt install pulseaudio
sudo usermod -aG audio $USER
# Log out and back in, then:
pulseaudio --start

Chrome crashes

If casty fails to start or Chrome crashes, try removing the browser cache:

rm -rf ~/.casty/browsers
casty  # re-downloads Chrome automatically

To reset all settings and profile data:

rm -rf ~/.casty

Acknowledgments

Input and navigation fixes were adapted from jjtseng93's fork, shared in issue #5.

License

MIT