Keryx Mail

Mail, calendar, contacts, and tasks in one Android app, written from scratch for JMAP and connected straight to your server. No account with us, ever.

Get it on Google Play What Premium adds
MailJMAP · IMAP CalendarCalDAV ContactsCardDAV TasksOne inbox

Why JMAP?

IMAP was designed when a mailbox lived on one machine and you visited it. JMAP was designed for phones: one connection, real push, and a single round trip where IMAP needs a dozen.

It carries contacts, calendars, and tasks over the same protocol, which is why Keryx can be one app instead of four that happen to share an icon.

Not on JMAP yet? Keryx also speaks IMAP, SMTP, CalDAV, and CardDAV in full, with compatibility depending on your provider’s protocols, authentication and enabled features, and it can subscribe to a read-only ICS calendar feed too.

Live on Google Play. Version 1.0.1 is available on Google Play and it is the mail app I use every day, against my own Stalwart JMAP server. The screenshots below are the ones on the store listing, taken from the shipping build.

The Keryx inbox: one message per card, a search bar and the four-tab bar for mail, calendar, contacts and tasksThe inbox, one card per message A message open in Keryx with its attachment chip and formatted bodyA message, attachments and all The Keryx calendar in month view with the day's events listed underneathCalendar, same app, same account
Keryx on an unfolded foldable: inbox list on the left, the open message on the rightUnfolded: list and message side by side Keryx tasks on an unfolded foldable: the task list beside an open task with its due date and priorityTasks, with the detail pane open

Free and Premium

The whole app is free. Premium is for the power user.

Included

Keryx Mail

Free on Google Play

One account, all four tools, nothing time-limited and nothing watermarked.

  • One active account with mail, calendar, contacts and tasks
  • JMAP, or IMAP and SMTP with CalDAV and CardDAV added on, plus read-only ICS feeds
  • Read, search, organise, compose formatted mail, reply and forward
  • Archive, delete, move, junk, tag and unsubscribe, one message at a time
  • Inline previews for images, PDFs and HTML; content previews for text, CSV, DOCX, XLSX, email and ZIP files. Office layout may differ. Supported audio and video play on the device
  • Events, invitations, and event and task reminders
  • Push on compatible JMAP and IMAP accounts, periodic sync, manual refresh
  • Light, dark and OLED appearance, phone and foldable layouts, a mail widget
  • Remote-image controls, backup and restore, cache controls, account removal

No ads, no analytics, no Keryx account.

Optional upgrade

Keryx Premium

$19.99 one time
No subscription

One permanent unlock through Google Play, tied to your Google account, not to a phone.

  • Additional accounts and a unified inbox
  • Scheduled send, snooze and advanced notification controls
  • Sending identities, signatures, templates and snippets
  • Follow-up reminders, saved searches, smart folders and private message notes
  • Turn an email into a linked task or a calendar event
  • Browse attachments across accounts, manage mailing-list subscriptions
  • Bridge provider contacts and calendars into Android Contacts and Calendar
  • Custom gestures, advanced appearance, launcher icons, the full widget collection
  • Vacation responder on services that support it
  • Today: current events, due tasks, waiting replies and returning snoozes in one view
  • Manual quick actions with retry and Undo
  • Work and Personal profiles with quiet hours and theme overrides

Purchases are handled by Google Play. Keryx never sees your payment details.

Light, dark and OLED

Three appearances out of the box, layouts that adapt to a phone or an open foldable, and an accent colour of your choosing. Premium opens the full appearance set and the launcher icons to match.

Tested against a hostile server

A purpose-built rig throws malformed headers, undecodable subject lines, raw 8-bit where the standard forbids it and broken calendars at the app on demand. The parser fails here so it does not fail on your phone.

Your accounts connect directly

No Keryx account or advertising SDK. Personal account traffic connects directly to the providers you configure. Google Play handles purchases and may process purchase diagnostics; optional fictional demo accounts are hosted separately. Remote images are blocked by default. Read the Keryx privacy policy for details.

Mail, calendar, contacts, tasks — one herald.

Keryx is the ancient Greek word for herald — the trusted messenger who carried word between cities and delivered it intact. That's the whole job here: mail, calendar, contacts, and tasks carried between you and your server, delivered faithfully, with no one else in the middle.