MailCraft

A clean-room, open-source desktop mail client in pure Rust, modelled on the classic Outlook workflow.

Module rail, ribbon, folder pane, message list and reading pane, the way you already work: rules, quick steps, conversations, search folders, calendar, people, tasks and notes. IMAP and SMTP accounts with offline sync. Runs natively on Linux, Windows, macOS and FreeBSD, and in the browser via WebAssembly.

A tour · What works today · Quick start · For agents · Architecture · Roadmap · License

_{The sample mailbox: folder pane with unread and [total] counts, date groups, unread bars, flags and categories, and the reading pane.}

A tour

Dark theme	Classic ribbon (Simplified is the default)
Calendar	Narrow windows: the folder pane minimises and the list and reading pane take turns

Why MailCraft

• The workflow you know. Behaviour, layout and feature names follow careful black-box observation of the classic desktop client: default folder order, unread and total badges, date groups, RE:/FW: handling, the quoted header on replies, the Rules Wizard, ribbon degradation as the window narrows.
• Yours. Open source (MIT OR Apache-2.0), local-first storage, standard protocols (IMAP, SMTP, JMAP) and standard files (EML, MBOX, MSG, iCalendar, vCard, CSV). No telemetry.
• Agent-drivable. Every action is a named command. The CLI, the JSON control channel and the MCP server drive the same commands the ribbon does.
• Never crash. No panics in non-test code, hostile-input fuzzing over every command, size caps on every parser.

What works today

Status: pre-alpha. See ROADMAP.md for honest per-area estimates and docs/parity.md for the feature catalog. Account types, push, POP3, JMAP, OAuth sign-in and where passwords are kept: docs/accounts.md.

• Mail: read, reply, reply all, forward (inline or in a window), drafts, delete/archive/move/copy, flags, categories, importance, Focused/Other, arrange by 13 keys, filters, conversations, search with a query language, search folders.
• Compose: rich text, spelling with suggestions, signatures, address auto-complete, attachments.
• Accounts: IMAP + SMTP with background sync, an offline queue, Outbox → Sent, Send/Receive.
• Organise: rules (Rules Wizard, run on arrival or on demand), quick steps, colour categories.
• Calendar, People, To Do, Notes: views, editors, meeting requests over iCalendar, reminders.
• Files: import and export EML, MBOX, MSG, ICS, VCF, CSV; print and PDF.

Quick start

Packages for Linux, Windows, macOS, FreeBSD and the web are published on the releases page (see docs/releasing.md). To build from source:

git clone https://github.com/MonkeySaint/mailcraft.git && cd mailcraft

# Desktop app with the built-in sample mailbox
cargo run --release -p mailcraft -- --sample

# Your own local profile (data in ~/.local/share/MailCraft by default)
cargo run --release -p mailcraft

# Local test mail servers for trying accounts without a real mailbox
cargo run -p mailcraft-testmail-app -- --help

Web build: see apps/mailcraft-web/README.md.

For agents: CLI and MCP

mailcraft-cli commands                 # every command id, label, location, shortcut
mailcraft-cli parity                   # catalog coverage summary
mailcraft-cli run --sample --cmd 'mail.reply' --query list
mailcraft-cli mcp --sample             # MCP server over stdio (see docs/mcp.md)

A running app can be driven over a local JSON control channel (--control-port N, see docs/control-protocol.md); mailcraft-cli mcp --connect 127.0.0.1:N bridges MCP to it.

Architecture

Layer	Crates	Job
L0	geom, mime	units and colours; RFC 5322 and MIME parse/build
L1	model, fonts	mailbox model, rich text, dates; bundled open fonts
L2	store, html, layout	local storage; HTML sanitising ↔ rich text; body layout
L3	render, net, formats, proof, search	rasteriser and PDF; IMAP/SMTP/JMAP/OAuth2; file formats; spelling; search
L4	engine	session, undo, command registry, feature catalog, sync
L5	mcp	MCP server
L6	ui-egui	the Outlook-style user interface
apps	mailcraft, mailcraft-cli, mailcraft-web, mailcraft-testmail-app	binaries

cargo xtask ci runs fmt, clippy, tests, the layer check, asset attribution, the licence allowlist, the parity floor and the wasm build. CI runs on GitHub Actions (.github/workflows/).

Roadmap

ROADMAP.md lists milestones, honest parity per area and what needs the project owner. Bugs and ideas go to the issue tracker.

License

MIT OR Apache-2.0, at your option (LICENSE-MIT, LICENSE-APACHE). Bundled fonts are under the SIL Open Font License; see NOTICE and ATTRIBUTION.md.

MailCraft is an independent project, not affiliated with or endorsed by Microsoft. Outlook is a trademark of Microsoft Corporation, used here only to describe the workflow MailCraft is modelled on.