A premium email client for macOS, built local-first and never proxied. A Rust engine does the work, a Swift application draws it at native speed, and everything, including the AI, runs on your machine.
Every mainstream client has quietly become a front end for somebody's server. ATS Mail is the other thing: an application, on your computer, holding your data.
Depth, in the places a working day is spent. None of this is a setting buried four levels down: it is how the client behaves out of the box.
First-time senders wait outside the inbox. Screen them in, file them to Feeds or Receipts, or screen them out, and the decision applies to everything they send from then on. Screening out compiles to a local rule, so the sender is never notified and nothing bounces.
Focus, VIP, Team, Customers, All. Five lanes across the top of the list, switched with keys 1 through 5. You decide what belongs in each one, which is the part every algorithmic inbox gets wrong.
Shift T goes full screen, one conversation at a time, keyboard only. Archive, snooze, flag, reply against a session goal, then land back exactly where you were.
An ordered list with STOP conditions, run inside the ingest transaction so mail never flashes unfiled. Test against your history first and it reports what would have matched.
Operators like from:, has:attachment and no-reply-in:3d compile straight to indexed queries. The footer tells you how many messages were scanned and how long it took.
Both columns, side by side. Nudge a stalled thread and it queues for tomorrow morning. A standing list of senders you never open sits one click from Feeds or blocked.
Every action posts a five-second toast, and Command Z pops the same log. Undo send is that same window, because the server operation simply waits its turn.
The Outbox queues everything and replays in order on reconnect. A failed send surfaces the actual server reason, per message, with send-now, edit and cancel.
Remote images are blocked by default and the tracker count is surfaced per message. Authentication results are shown rather than buried. Lookalike domains are caught with Unicode confusable detection. Tokens live in Keychain. And a unit test asserts the app can only reach your own mail servers, which is what turns “never proxied” into a property of the build rather than a promise on a website.
Measured against a seeded 250,000 message store on Apple Silicon. These are not aspirations in a backlog: a pull request that misses one of them fails.