Otter Mail
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Otter Mail for iOS is on TestFlight

Email, calm and fast. A quiet mail client for Gmail, Outlook and IMAP, with an agent that does the busywork. On your Mac, on Linux, in your browser and on iOS. Your mail stays on your device.

Download for Mac and Linux Open in your browser

GmailOutlookIMAPClaude CodeCodexOpenRouterHermesOpenClawChrome extensions1Password

Otter Mail with a client's message open and the chat window over it: asked to file the Northwind mail, archive the week's newsletters and draft a reply, Claude did all three and lists every conversation it updated and the draft it created.
Ask in your own words, over the mail you're reading. The agent files, archives and drafts with Otter Mail's own tools, then lists everything it changed.

Every mailbox, one place

Gmail, Outlook and IMAP, side by side in one sidebar. Rename, color and reorder them; they follow you to every device.

Instant, and offline

Mail opens from a local cache with full-text search, so it is fast and keeps working without a connection.

Made for the keyboard

Rebindable shortcuts, a command palette, and undo for what you do, sending included.

Labels and views

Gmail labels nested as you made them, Outlook's folders and categories, plus saved views that filter across every mailbox.

Live on every device

New mail arrives the moment it lands, with notifications and an unread badge. Sign-in codes come with a Copy & trash button.

The small things

Send later and snooze, on-device translation, calendar invitations you answer in place, one-click unsubscribe, seven themes and your own.

An agent, if you want one

Claude Code, Codex, OpenRouter, Hermes or OpenClaw, on your own account, in a small window over your mail. Off until you set it up.

Wherever you are

A Mac and Linux app that updates itself, the same app in any current browser, and a native iOS app. Sign in once and your mailboxes and settings are there.

A workspace for the agent's work

The AI workspace: the chat on the left, and on the right its tabs, one for each conversation it read or changed and one for the reply it drafted, open and ready to send.
Open any chat in the workspace: the conversation beside the mail, drafts and pages it read or made, each in a tab. Chats follow you to every device.

A browser beside your mail

Otter Mail with a conversation open and a web page in the browser panel beside it, with its own tabs and address bar.
On the Mac and Linux, links open in a tab beside your mail. Add extensions from the Chrome Web Store and pin them to the toolbar: 1Password unlocks there and fills in your sign-ins.

A look inside

The agent asking first: Allow Claude to send email?, with the message it will send, and Deny or Allow once.
Nothing is sent without your yes.
A calendar invitation with Yes, No and Maybe above the message.
Answer invitations where they land.
A sign-in email with its code, 482913, in a card above the message, and a Copy & trash button.
Sign-in codes, copied in one click.

Your mail stays yours

Otter Mail reads your mail from Gmail, Outlook or your IMAP server directly on your device and keeps its mailbox cache there. An Otter account, optional on the Mac, syncs your mailboxes, preferences and agent chats and wakes your devices when mail arrives. If you use the OpenRouter agent, its chat history and mail returned by tools are stored on our server and sent to OpenRouter and the selected model provider. No analytics, no tracking. Details are in the privacy policy, and the code is open source under the MIT license.