What is Proton Mail Bridge?

This desktop application from Proton AG brings end-to-end encrypted email to standard email clients. It runs locally on Windows, macOS, or Linux and creates IMAP and SMTP servers that handle encryption transparently. Compatible clients include Microsoft Outlook, Mozilla Thunderbird, and Apple Mail. The software requires a paid Proton Mail subscription and a supported keychain for credential storage. On Linux this means GNOME Keyring or pass; Windows and macOS use their native credential managers. Official packages are provided as DEB, RPM, and PKGBUILD for Ubuntu LTS and Fedora Workstation. The code is licensed under GPL-3.0 and includes automatic updates verified by a launcher that checks binary signatures.

Should you self-host Proton Mail Bridge?

Proton Mail Bridge scores 60/100 on selfhost.directory (how scoring works) and ranks #11 of 33 in Communication. It has 1 574 GitHub stars.

It shipped 10 stable releases in the past year. The latest, v3.27.1, came out on 8 October 2026. New versions land roughly every 3 weeks.

Setup is moderate: expect some configuration beyond a single command. It is GPL-3.0-licensed and written mostly in Go.

Its closest alternative on selfhost.directory is Jitsi Meet (79/100, 30 158 stars). It scores higher overall, so compare the two before you pick. See Proton Mail Bridge vs Jitsi Meet side by side.

Features

Automatic Updates
Background operation
CLI and non-interactive modes
End-to-end encryption for email clients
Local IMAP/SMTP servers
Offline Access
Works with Outlook, Thunderbird, Apple Mail

FAQ

Do I need a paid Proton plan?

Yes, Proton Mail Bridge is available only with a paid plan that includes Proton Mail.

Is Proton Mail Bridge as secure as Proton Mail's apps?

Proton Mail Bridge was built from the ground up with security in mind. Your passwords never leave your machine, and Proton never permanently stores your PGP keys or decrypted message data on disk.

Which email clients are supported?

Proton Mail Bridge works with popular email clients such as Microsoft Outlook, Apple Mail, and Mozilla Thunderbird on all popular operating systems.

What is Proton Mail Bridge?

Proton Mail Bridge is a desktop application that runs in the background, encrypting and decrypting messages as they enter and leave your computer. It lets you add your Proton Mail account to your favorite email client via IMAP/SMTP by creating a local email server on your computer.