1. Postal
2. Mailcow
3. Cuttlefish
4. Apache James
5. Haraka
6. Modoboa
7. Postfix
8. Maddy
9. Dovecot
10. Poste.io
11. iRedMail
12. Mailu
13. hMailServer
14. Haraka
15. Zimbra
16. Mail-in-a-Box
17. Exim
18. Sendmail
19. Qmail
20. Citadel
21. SquirrelMail
22. Horde
23. Apache James
24. Axigen
25. Docker mailserver
26. Roundcube
27. Open-Xchange
28. Hakara
29. Poste.io
30. SoGo
31. Mailpiler
32. MailSlurper
33. WildDuck
34. Salmon
35. Open Trashmail
36. Neuron Mail Server
37. Magama
38. Inbucket
39. Mox
40. Magma
![](https://taylanguneyaktas.com/wp-content/uploads/Open-Source-Email-Servers-1870x1870.png)