macOS 13 or later · Apple Mail
AI mail reply for the Mac, inside Apple Mail
Most AI email tools ask you to move to a new client and route your mail through their servers. MailTwin does neither. It writes replies inside Apple Mail, in your own voice, using the AI provider you pick with your own key — or entirely on-device, with no key and no network.
What it does
Select a message in Apple Mail. Type the points the reply should make — “Friday doesn’t work, propose Tuesday, ask about the invoice”. MailTwin writes the full reply. You read it, change anything you want, and send it yourself.
It also summarizes long threads, pulls out action items, translates, and improves a draft you have already written. Improve and My Style appear as buttons inside Apple Mail’s own compose window.
Your voice, per account
When you ask it to, MailTwin reads your sent mail once, locally, and learns how you actually write — separately for each account. The work mailbox doesn’t end up sounding like the personal one, and switching mailbox switches the register with it. Nothing is indexed at launch, on a timer, or in the background; it only happens when you start it.
Which AI, and where your mail goes
Eight providers ship in the app: Apple Intelligence, Ollama, Claude, ChatGPT, Gemini, Grok, Groq and DeepSeek. You supply your own key and the request goes straight from your Mac to that provider. There is no MailTwin server anywhere in the AI path — we operate no proxy, so there is nothing of yours for us to hold.
With Apple Intelligence (macOS 26 on a supported Mac) or Ollama, nothing leaves the machine at all. No key, no account, no network request.
It never sends anything by itself
Every reply is read by you before it goes. A local validator checks the output before it is ever written into a draft, and rejects anything that invents a fact, changes a number, date, link or amount, or adds a sign-off you didn’t write. If it can’t verify what it’s about to do, it fails and leaves your draft alone.
Common questions
Do I have to switch mail apps? No. It runs in the menu bar and as an extension inside Apple Mail. Your accounts, rules and mailboxes are untouched.
What does it cost? $19.90 once for one user, $49.90 for five. No subscription. 30-day full trial, no card required.
What about other languages? The interface ships in fifteen. Replies are written in the language of the message you’re answering.
Requirements? macOS 13 or later and Apple Mail. Apple Intelligence as the engine needs macOS 26 on a supported Mac.
Covered by Italiamac · iPhoneIslam · ifun.de · Faq-Mac · Michael Tsai
MailTwin is a menubar app for Apple Mail on macOS 13 or later, built by Smilodon AS in Norway. mailtwin.ai · email time calculator · reply to emails faster