We built this because we needed it ourselves.

Trumailo started as an internal tool. We were shipping email-heavy products — transactional notifications, sales sequences, lifecycle nudges — and our bounce rates kept dragging our sender reputation down. Every commercial email-verification API we tried was expensive, opaque about what it actually checked, and slow enough that we had to wire it through a queue.

So we wrote our own. Eight signals per address, real SMTP RCPT TO handshakes, catch-all probes, disposable-domain lists, provider mapping. Cached in Redis so the hot path stays under 10 milliseconds. Async deep verification on a NATS queue so batch jobs don't block your response.

It worked. We stopped bouncing. Our open rates lifted. And other people kept asking if they could use it — so here we are.

Trumailo is open source, free during public beta, and run by a tiny team that answers its own emails. We won't add a sales bot. We won't put your card details in a wallet you can't see. We treat the email ecosystem like the public infrastructure it is.