bun-smtpSMTP server for Bun

Drop-in replacement for smtp-server. Zero dependencies. Bun-native.

import { SMTPServer } from "bun-smtp";

const server = new SMTPServer({
  authOptional: true,
  onData(stream, session, cb) {
    // handle incoming mail
    cb(null);
  },
});

await server.listen(2525);

⚡

Ultrafast

Up to 3x faster than smtp-server on large payloads, 54% faster on concurrent transactions.

🐰

Bun-native

Built on Bun.listen(), socket.upgradeTLS(), and Bun.CryptoHasher. No Node.js compat layer.

🔄

Drop-in replacement

Same constructor options, callbacks, and event names as the smtp-server npm package. Minimal migration effort.

✨

Delightful DX

Fully typed API, sensible defaults, and minimal boilerplate.