Personal mail is the one case I think where hosting your own MTA still makes sense when you want to own the addresses and the data. You still have to solve for

Personal mail is the one case I think where hosting your own MTA still makes sense when you want to own the addresses and the data. You still have to solve for deliverability, which is something I hope to never have to do. Posthorn is built for the opposite end of that, you've already decided you want to use a transactional provider for app mail and you just want to stop having to deal with wiring it into all of the things. Obviously for a big production app you build your own mail service, but for gluing together a bunch of different apps you're self hosting, I think this makes sense and addresses a real issue. If you want an API piece to augment what you already have, Posthorn might still be useful regardless of how the rest of your mail is set up. A Posthorn JSON endpoint is just a POST with Bearer auth and an idempotency key. Example from my docs: curl -X POST https://posthorn.yourdomain.com/api/transactional https://posthorn.yourdomain.com/api/transactional \ -H "Authorization: Bearer $WORKER_KEY_PRIMARY" \ -H "Content-Type: application/json" \ -H "Idempotency-Key: reset:user-123:$(date -u +%FT%H)" \ --data '{ "to_override": "bob@example.com", "subject_line": "Reset your password", "message": "Click here: https://app.example.com/reset/abc https://app.example.com/reset/abc" }' Could run alongside your existing mail server. It's a small enough overhead that the juice might be worth the squeeze.