Lightning fast
A Rust core runs sync, search and downloads on their own prioritised lanes, so reading and writing stay instant. Folders with a million messages and mailboxes of 100 GB and more open without a wait.
Whole-of-company AI mail
Email at the speed of thought.
Kestrel is the first whole-of-company AI-integrated mail platform. Lightning fast, secure and wise: mail, calendar and people in one desktop app for Windows, macOS and Linux.
Download early access Why KestrelSecure
Your company's mail stays on your company's own servers. Mail content is sanitised and remote content is off until you allow it. Every installer and update is signed and published with a checksum.
Wise
Kestrel's AI works for the whole company, not one inbox at a time. It runs alongside your own mail servers, so what your organisation knows can help everyone in it, inside your walls.
Built for real work
Everything you expect from a desktop mail client, without the bloat.
Kestrel looks and works the way people already know, then gets out of the way. It connects to your organisation's mail server over Exchange ActiveSync, with push for new mail.
- Never lose a draft. Drafts save as you type and reopen exactly as they were after a restart or crash.
- Many accounts. Several mailboxes on several servers, each syncing on its own; one slow server never holds up the rest.
- Huge mailboxes. Headers indexed locally for instant search; bodies and attachments cached within a disk budget you set.
- Mail, calendar and people. One window, one fast app.
- Looks right everywhere. Bundled fonts, so Linux looks as good as Windows and macOS.
- Updates itself. Signed automatic updates on every platform.
Try Kestrel
Early access for Windows, macOS and Linux. Signed installers, with a checksum next to every file.