Frostmail

A Linux mail client that works like Apple Mail.app, without looking like a GNOME or KDE app. Pre-release: it syncs, reads, searches and sends generic IMAP, Gmail and iCloud accounts, and is in its daily-driver trial (M4). Contacts, calendars and tasks over CardDAV, CalDAV and Google Tasks, invitations answered from the reader, and a To-Do bar beside the inbox are arriving (M4.5). See the roadmap.

_{The screenshots show made-up mail (app/e2e/showcase) in the real app; make screenshots retakes them.}

• maild is a per-user Go daemon that owns sync, a SQLite cache with full-text search, and a JSON-RPC socket.
• The app is Tauri v2 with a React UI in the system WebKitGTK.
• mailctl is a command-line client of the same socket.

Develop

Requirements: Go 1.27 and mise install (golangci-lint) on the host; nsl for the app toolchain; incus for the test mail server.

nsl create frostmail --distro debian:13
nsl run -m frostmail --root bash dev/nsl/provision.sh "$(id -un)"
dev/incus/mailtest.sh up
make check          # host: generated files, vet, lint, unit tests
make engine-it      # integration tests against the test mail server
make ui-test        # nsl: typecheck and UI tests
make app-run        # nsl: maild plus the built app

make help lists every target. Architecture starts at docs/design/overview.md; agents start at AGENTS.md.

License

MIT. third_party/go-imap is MIT, from emersion/go-imap, with the patches in its FROSTMAIL-PATCHES.md.