Sendlr is a developer-first email API running on a mail transfer agent we're writing in Rust. No reseller in the middle. Every hop, every IP, every SMTP reply, visible. We're warming up for a private beta.
249,912 acknowledged emails survived ten hard crashes of the MTA.
Measured on a single cloud server with fsync on, into a test sink.
Every email is on disk before the API returns 202 Accepted.