Open source mail projects
Every project in the registry tagged mail, ranked by real GitHub adoption.
Open-source mail server with unlimited sending & AI tools
BillionMail gives you open-source MailServer, NewsLetter, Email Marketing — fully self-hosted, dev-friendly, and free from monthly fees. Join the discord: http
Cross-platform chatbot framework made with love
Frequently asked questions
How many open source mail projects are there?
This registry tracks 3 projects tagged mail, with 37,432 GitHub stars between them. The most-adopted is Billion Mail at 15,612 stars.
Are these mail projects free to use?
Yes — 3 of the 3 carry an explicit open-source licence across 2 distinct licences, so there is no licence fee. Where a project also sells a hosted or enterprise version, the self-hosted path remains free.
Which mail project should I choose?
The list above is ranked by GitHub stars, but stars measure attention rather than fit. Check three things on each card: the licence (permissive versus copyleft), the language it is written in, and the last-push date — a high-star project that has not been pushed in a year is a liability.
Are these mail projects still maintained?
1 of the 3 were pushed in the last 90 days, and every card shows its exact last-push date so you can see the rest. Sort your shortlist by that date before committing to a migration.