Side by side
Postfix vs Stalwart Mail Server
Both stand on email server software. Which one you can start free with, which one lets you read the code, and what each costs once you pay.
Free plan LinuxMacSelf-hosted
Visit Postfix 
Free plan APILinuxMac+3
Visit Stalwart Mail Server The facts
| Postfix | Stalwart Mail Server | |
|---|---|---|
| Free plan | Yes | Yes |
| Open source | Not published | Not published |
| Runs on | Linux, Mac, Self-hosted | API, Linux, Mac, Self-hosted, Web, Windows |
| Lowest paid plan | Not published | Enterprise — 50,000 to 99,999 mailboxes: $1.09 per mailbox a year |
| Plans published | None | 16 |
| Maker | Not published | Not published |
| Website | postfix.org | stalwart.email |
| On email server software | #21 of 33 | #17 of 33 |
Alternatives to Postfix Alternatives to Stalwart Mail Server The whole list