Letterdock

A free, open-source email client for Windows. Add as many accounts as you like. No limits, no ads, no subscription.

Website: https://voydapps.github.io/letterdock/

Made by voyd.

Features

• Unlimited email accounts (IMAP/SMTP), all in one place
• One inbox for all accounts, conversations, search across accounts
• Send later, rules that sort mail for you, and offline reading
• Snooze, one-click unsubscribe, quick replies and a command box
• Notification buttons: Mark as read, Archive and Delete
• Open and save .eml files (Letterdock appears in Windows Default apps for .eml; it never makes itself the default)
• Keyboard shortcuts in Gmail and Outlook styles
• Dark mode for emails and blocked pictures until you allow them
• Automatic updates from GitHub Releases
• Your mail is stored on your own PC
• Opens mailto: links when you choose it as your default mail app
• Small installer, no admin rights needed

Screenshots

One inbox for all your accounts, here in dark mode.

The same window in light mode. Letterdock follows your Windows setting.

Replies grouped into conversations	Write now, send later

Rules sort your mail for you	Pictures are blocked until you allow them

Bright emails in dark mode	Add as many accounts as you like

Website: https://voydapps.github.io/letterdock/

All pictures use made-up people and mail. Regenerate them with npm run site:screenshots.

Download

Get the latest installer from the Releases page. Download Letterdock-Setup-<version>.exe and run it.

The installer is not code-signed yet. Windows SmartScreen may show "Windows protected your PC". This is expected. Click More info, then Run anyway.

Gmail: use an app password

Gmail does not accept your normal password in desktop mail apps. Use an app password instead:

1. Turn on 2-Step Verification in your Google account.
2. Open https://myaccount.google.com/apppasswords and create an app password named "Letterdock".
3. In Letterdock, add your Gmail address and paste the 16-letter app password.

Outlook / Microsoft accounts

"Sign in with Microsoft" needs an app registration (client ID). It is coming. Until then, other IMAP accounts work as usual.

Build from source

You need Node.js 24 (see .nvmrc) and Windows.

npm ci
npm run dev        # start the app with hot reload
npm run typecheck
npm run lint
npm test
npm run dist       # build the installer into release/

Local installer builds can be blocked by Windows Smart App Control. The official installers are built by GitHub Actions: bump the version in package.json, commit, then push a tag like v0.2.6. The installer appears on the Releases page.

Set LETTERDOCK_DATA_DIR to run with a throwaway data folder. Set LETTERDOCK_MS_CLIENT_ID to test "Sign in with Microsoft" with your own app registration.

Privacy

Letterdock has no telemetry and no analytics, and no Letterdock servers. Your mail, accounts and settings stay on your PC (in %APPDATA%\Letterdock). Passwords are kept in Windows protected storage (DPAPI). The app talks to your own mail servers, to GitHub (to check for updates), to your email domain and Thunderbird's public settings list (to find server settings when you add an account), and to image servers only after you allow pictures.

License

MIT (c) 2026 voyd