The interesting part is the dual model - it's fully open source (MIT license) so you can self-host, but I also offer a hosted service starting at $4.99/month.
Tech stack of open-source version: Go + PostgreSQL + Redis, containerized with Docker. The hosted service saves users $30-150+/month compared to traditional providers, while the open source version gives complete control.
Key insight: Most small businesses don't need complex automation - they need reliable, simple email sending without breaking the bank.
Looking for feedback on the approach and feature set!