For Mac and iPhone. Now in public beta.

Native email.
Search in your own words.

Find the email you mean. Choose who reaches your Inbox.
Keep your accounts together in an app that feels at home.

Try Letterslot on TestFlight See search in action

Public beta for macOS 26 and iOS 26 or later. TestFlight required.

Letterslot on Mac: Inbox, nested sidebar labels and an open conversation with sample messages. — The Mac app. Inbox shown with sample messages.

Your accounts. Together.

Gmail
Yahoo
Fastmail
iCloud
IMAP

Use one Inbox or switch between accounts. Gmail connects through Google’s API; other accounts connect directly over IMAP and SMTP.

Outlook is next. Planned for mid-November 2026, about three weeks from our 24 October update.

On-device AI search

You remember the email.
Not the exact words.

Describe what you’re looking for. Letterslot combines text search, useful filters and on-device semantic matching to help you find it.

Native Letterslot search preview showing three sample PDF messages from Will, with person, keyword and date filters. — Search preview with sample messages. Native results and filters from Letterslot.

Start with what you remember.

A person, a phrase or an attachment. Type it into search and refine with the filters you can see.

Search stays on your device.

The local index and semantic model run on your Mac or iPhone. Search can also ask your provider directly for mail that isn’t downloaded.

Useful with or without AI.

Text and filters work independently. Semantic matching uses Apple’s English sentence model when it’s available on your device.

Built for everyday mail

Familiar tools.
A little more control.

Choose your senders.

Unfamiliar senders appear in Screening. Accept them, skip the Inbox or block them. AI can explain a message; you make the decision.

Keep the history together.

Browse a sender’s conversations, receipts and updates in one place. Organise with nested labels without losing the sender’s history.

Write like a Mac app.

Rich text, attachments, inline images and signatures. Separate compose windows on Mac, with native editing, menus and keyboard shortcuts.

Read from your device.

Downloaded mail opens from a local SQLite cache. Background sync and optional on-device processing run separately from reading.

Keep things moving

Make each swipe
your own.

Choose what happens when you swipe. Read, snooze, archive or trash — with your preferred actions on each side.

Letterslot swipe settings: choose a full-swipe and second action for each direction. Defaults are Read or Unread, Snooze, Archive and Trash. — The app’s native swipe settings. Choose your full-swipe and second actions.

Private by design

Your provider.
Your device. Your mail.

The app downloads mail directly from your provider. Messages, headers and attachments don’t pass through Letterslot’s servers.

Search and Apple Intelligence processing run on your device. Credentials stay in Keychain. The privacy policy explains storage, optional services and the planned IMAP notification connection.

Read the privacy details

Letterslot public beta

Try it with your mail.

Available for Mac and iPhone through TestFlight.
Help shape what comes next.

Join the public TestFlight See the roadmap →

Native email.Search in your own words.