Sterna Mail

All your mail. None of the baggage.

Private email client for JMAP and IMAP/SMTP. No Google services, no tracking.

Free software under the GPLv3. No ads, no tracking, no Google services.

Named after the Arctic tern, which flies the longest migration of any animal. I liked the idea of mail that travels light and always finds its way home.

The protocol

Built for JMAP, fluent in IMAP

JMAP is the modern successor to IMAP. Instead of asking every folder what has changed, a single request brings back everything new, so mail arrives sooner and the battery lasts longer. Classic IMAP and SMTP work just as well, so no existing mailbox is ever out of reach.

IMAP IMAP: one round trip per folder, on every check

JMAP JMAP: one request, everything that changed

Guarantees

What it does, and what it doesn't

No Google, no FCM

New mail is pushed from your own server to your phone over JMAP EventSource, IMAP IDLE or UnifiedPush. Play Services are never required.

Nothing watches you

No analytics, no advertising, no crash reporting, no third-party SDK. The app only connects to hosts you chose or that a message you received names, and the project has no server of its own to receive anything.

Remote content blocked

Remote images and tracking pixels stay unloaded until you ask for them, and tracking parameters can be stripped from links before they open.

Reproducible builds

F-Droid rebuilds each release from the published source and checks it byte for byte against the app it hands you. Anyone can read and audit that source.

In daily use

A complete mail client

Sterna Mail is a free, private email client for Android. It is built for JMAP, the modern successor to IMAP, and works just as well with any IMAP/SMTP provider.

Reading

Several accounts, JMAP and IMAP side by side, with a unified inbox that works offline
Conversations, search as you type and snooze

Writing

Several identities, each with its own signature
Undo send and scheduled send

Privacy and security

OpenPGP encryption through an app such as OpenKeychain
Remote images and tracking pixels blocked by default, app lock with fingerprint or PIN

Setup and notifications

Setup from your email address alone, or a manual form when the domain publishes nothing
Push notifications without Google, over JMAP, IMAP IDLE or UnifiedPush
Available in eleven languages

A look