MailCraft

Local-first email: an open-source, clean-room alternative to Microsoft Outlook, written in Rust.
By Zinadin Zidan and the MailCraft contributors.

mailcraft.dev · Download · Changelog · Roadmap

MailCraft gives you the everyday Outlook mail workflow with your own mail servers. It keeps a copy of your mail on your computer, so it works offline.

Features

• Familiar: three panes, a ribbon and the usual Outlook shortcuts. Drag messages onto folders.
• Accounts: IMAP or POP with SMTP, JMAP, and Exchange Online (Graph) or on-premises (EWS). Sign in with Gmail or Microsoft 365, see All Inboxes, and open or export .pst files.
• Works offline: every folder is kept on disk and synced in the background. Changes you make offline go to the server when you reconnect.
• Reading and writing: conversations, formatted HTML, picture thumbnails, rich-text replies, signatures, drafts, an Outbox, Print and Save as PDF.
• Organising: archive, flag, pin, snooze, categories, Focused and Other, rules, and Undo.
• Search: works offline, with from:, subject:, has:attachment, is:unread and more.
• Calendar and people: day, week and month views, meeting invitations, tasks, a To-Do Bar beside the mail, an address book, and CalDAV/CardDAV, with a mail account or on their own, from any such server (Nextcloud, Baïkal, SOGo, Radicale and others).
• Private and secure: MailCraft talks only to your servers, always over TLS. Passwords stay in the system keychain. Remote pictures load only when you ask. S/MIME and OpenPGP sign and encrypt, and the message you're writing says whether everyone in it can receive it encrypted.
• Everywhere: Windows, macOS, Linux and the browser (JMAP accounts only), in 15 interface languages.
• Scriptable: every action is a command with an id. The ribbon, shortcuts, the CLI and --cmd all run the same commands.

Install

Download an installer from mailcraft.dev, which offers the file for your system, or from the Releases page:

• Windows: .msi, or a portable zip.
• macOS: .dmg.
• Linux: AppImage, .deb, .rpm, Flatpak or .tar.gz.
• FreeBSD: a tarball.

To run MailCraft portably, put a portable.txt file beside the app. It then keeps its data in a MailCraftData folder next to it.

Build and run

cargo run --release -p mailcraft -- --sample   # local sample mailbox; drop --sample to add an account
cargo run -p mailcraft-cli -- commands         # CLI: add, sync, list, read, search, send, run
cd apps/mailcraft-web && trunk serve           # browser: http://127.0.0.1:8774/?sample

• The CLI reads your password from MAILCRAFT_PASSWORD, or asks for it. It never stores it.
• MailCraft keeps its data in %APPDATA%\MailCraft (Windows), ~/Library/Application Support/MailCraft (macOS) or ~/.local/share/mailcraft (Linux). To use another folder, pass --data DIR or set MAILCRAFT_DATA.
• To put the web build on your own site, see hosting the web build.

Documentation

• Setting up your email account
• Switching from Outlook
• Opening a .pst file without Outlook
• Running MailCraft from a USB stick
• What each version added
• What comes next
• What's still missing
• How MailCraft is built
• How sync works
• How test builds update themselves
• Microsoft and Google sign-in
• Hosting the web build

Contribute

• Start with how MailCraft is built.
• Follow the project rules in CLAUDE.md: no crashes, no Microsoft assets, clean room.
• Run cargo xtask ci before every commit.
• To fuzz the parsers, see fuzzing.
• The installer scripts live in packaging/. The Release workflow (release.yml) runs them and publishes a release.

License and credits

MailCraft is dual-licensed under MIT OR Apache-2.0.

It is built on mail-parser, mail-builder, imap-proto, lettre, rustls, html2text, hayro and egui. .pst files go through MailCraft's own crate, written from Microsoft's published specification.

Microsoft Outlook is a trademark of Microsoft. MailCraft is not affiliated with Microsoft and uses none of its code, icons or assets.