MailTwin

MailTwin sits alongside Apple Mail and writes the reply for you. Type a few keywords, or just the points the answer needs to cover, and it drafts a complete, editable response in the voice it has learned for that particular account — so work mail and private mail keep sounding like two different people.

You choose the AI: eight providers, from Claude, ChatGPT and Gemini to Apple Intelligence and local models via Ollama. The key stays in your macOS keychain and requests go from your Mac straight to the provider, with no MailTwin server in between. Alongside drafting there is Inbox Cleanup, which reads only metadata and shows you every action before it happens, plus follow-ups, action items and translation.

MailTwin costs $19.90 once for a single Mac, or $49.90 for five, after a 30-day trial with everything unlocked. All 1.x updates are included. One thing worth knowing before you buy: the app itself has no subscription, but a cloud provider bills you per token for the key you bring — usually cents a day. Apple Intelligence and Ollama run on your own machine for nothing.

Why no subscription? Most AI mail tools charge monthly and take their cut of the tokens on top. MailTwin sells you the app once and lets you buy the intelligence at cost — or run it locally for free.