QQueue.
An open-source platform for campaigns, transactional email, queues, retries, tracking, and webhooks — running on your own SMTP providers. You keep the control; QQueue handles the plumbing.
Sending one email is easy; running email is not. Raw SMTP puts a message on the wire but gives you no queue, no retries, and no real idea whether it arrived — so teams bolt on a job runner, a tracking pixel, and a half-finished bounce parser until campaign logic leaks across the app. Hosted platforms fix it until the bill scales with every contact and your sender lives on someone else's IP.
A self-hosted layer on top of any SMTP provider (Mailcow, SES, Postmark, Resend, Brevo). A BullMQ + Redis queue and workers handle sending and campaign fan-out with backoff and attempt tracking; opens and clicks are signed with HMAC tokens; messy ESP bounce/complaint payloads are normalized to one inbound webhook shape. Everything ships behind a documented REST API and a typed TypeScript SDK, and the whole stack comes up via Docker Compose behind Caddy/TLS.