Skip to content
Simone Silvetti
← All projects

lettera

Rust · Tauri 2 · Svelte 5 · SQLite · Flatpak • Source on GitHub

lettera is a desktop email client that does a few things and stays out of the way: monospace type, thin rules, no menus, and only a handful of icons (the folders on the left, the logo, a paperclip for attachments). It is driven from the keyboard, Vim style (j/k to move, e to archive, r to reply, / to search), and anything without a shortcut lives in a command palette opened with :. Every key hint on screen is also a button, so the mouse works too.

inbox  12 unread · 240                                      simone@example.com
──────────────────────────────────┬────────────────────────────────────────────
 TODAY                            │  Q4 planning
▌■ Anna Rossi 3    Q4 planning    │  3 messages · Anna Rossi, Marco Bianchi
   Marco Bianchi   October invoice│ ───────────────────────────────────────────
──────────────────────────────────┴────────────────────────────────────────────
hjkl navigate · ⏎ open · e archive · r reply · / search · : commands  sync ●

What it does

  • Accounts: any IMAP/SMTP provider, and Gmail with an app password or OAuth2, side by side.
  • Mail: read, search (full text), archive, delete, move, reply, forward and write plain-text email with attachments and a signature. Conversations are grouped into threads.
  • In the background: it syncs every folder, gets new mail instantly through IMAP IDLE and shows a desktop notification. Closing the window leaves it in the tray, and it can start hidden with the session.
  • Drafts save themselves every few seconds and go to the server's Drafts folder, so other clients see them.
  • Omarchy: on Omarchy it takes its colors from the current theme and recolors live when the theme changes.
  • Configuration is a single TOML file, reloaded as soon as it is saved. Passwords and tokens live only in the system keyring.

How it is built

  • crates/core is the engine in Rust, with no UI dependency: IMAP (async-imap), SMTP (lettre), OAuth2, MIME parsing, SQLite with FTS5 for search, sync and threading. It is tested on its own.
  • A thin Tauri 2 layer exposes it to a Svelte 5 interface, which only draws and sends commands.
  • Each account keeps three IMAP connections: one for background sync, one for user actions, one in IDLE on the inbox. Actions are optimistic: the list changes at once and the server follows; if the server disagrees, the folder is resynced.
  • HTML email is sanitized when stored and shown in a sandboxed frame with remote images blocked.

The tests cover parsing, threading and sync against a fake IMAP server, and an integration suite runs the whole engine against real Dovecot and Mailpit servers in Docker. A GitHub Actions workflow builds the Flatpak package and attaches it to each release.

I built lettera together with Claude Code: about 10,000 lines of Rust and 3,500 of Svelte and TypeScript. I set the direction, the design and the priorities, and tried it on my own mail while the agent wrote and tested the code.

Install

On Linux, with Flatpak:

curl -LO https://github.com/simonesilvetti/lettera/releases/latest/download/lettera.flatpak
flatpak install --user lettera.flatpak

lettera is free software, released under the GPL-3.0-or-later.

← All projects