

BillionMail gives you open-source mail server, newsletter, email marketing — fully self-hosted, dev-friendly, and free from monthly fees.
Cost / License
- Free
- Open Source (AGPL-3.0)
Platforms
- Self-Hosted
- Docker

PostStack is a developer-first transactional email API for European teams. Send via REST or SMTP, host IMAP/POP3 mailboxes on your own domains, and run broadcasts — all from EU infrastructure with transparent pricing from €5/mo.
Cost / License
- Freemium
- Proprietary
Platforms
- Online
- Software as a Service (SaaS)






