Gridlink

A fast, private JMAP email client for Android, supporting classic IMAP and SMTP too. No ads, no tracking, no Google.

Note

Gridlink Mail is a fork of Sterna Mail, licensed under the GPLv3 and reused under its terms. The mail engine, sync layer, OpenPGP support, and most settings are the original author's work. This fork changes the front end and the setup flow. It is not an official Sterna release.

Features

Reading and organising

- Unified inbox across multiple accounts over JMAP and/or IMAP, with SMTP for sending, fully offline with a local cache. - Conversation view with collapsed threads and message counts. - Nested folders shown as a collapsible tree, with create, rename, and delete. - Configurable swipe actions, star, archive, delete with undo, multi-select bulk actions, snooze, report spam, empty trash, sort, and an unread-only filter. - Search-as-you-type with server-side and instant local results, plus advanced filters. - Calendar invites are previewed as event cards and can be added to your calendar app with one tap.

Writing and sending

- Compose with recipient chips, autocomplete, validation, multiple identities with their own signatures, attachments, and drafts. - Undo send, schedule send, and reminders for missing attachments or large recipient lists. - Opens mailto: links from any app, prefilled with addresses, subject, body, CC, and BCC.

Accounts and setup

- Add an account with email and password using JMAP autodiscovery, password-free OAuth 2.0 sign-in, or manual IMAP and SMTP with provider presets. - Per-account colour, sync window, and notification toggle. - Encrypted credential storage with Android Keystore, and app lock via biometric or PIN. - Optional publication of CardDAV and CalDAV contacts and calendars into Android as a real system account. Off by default and read-only.

Encryption

- OpenPGP via OpenKeychain for reading and sending signed and/or encrypted mail on both JMAP and IMAP/SMTP. - Decrypted content is never written to disk.

Notifications

- Push for new mail without Google or FCM, using JMAP EventSource, IMAP IDLE, or UnifiedPush. - Grouped per account, with quiet hours. - Server-side vacation responder and Sieve filter rules, plus mailbox quota display.

Offline by construction

Every screen reads the local database and only the local database. Syncing writes into that database and never renders anything. The app opens on your mail, not a spinner. A refresh never blanks the screen. Messages open offline, with any previously opened attachments. Anything done offline is queued in a persistent outbox and sent when the network returns.

Privacy

No tracking, no ads, no analytics, no Google services. Remote images and tracking pixels are blocked by default. Tapped links can be stripped of tracking parameters and confirmed before opening.

Requirements

- Android 8.0 (API 26) or newer - A JMAP or IMAP/SMTP mail account

Languages: Dutch, English, French, German, Italian, Polish, Portuguese, Russian, Spanish

The app respects the system language by default, with a per-app override in Settings.

License

GNU General Public License v3.0