| Price from | $0.83/mo | — |
| Free plan | — | — |
| Free trial | Yes | — |
| Open source | — | — |
| Web | Yes | — |
| macOS | — | Yes |
| Linux | Yes | Yes |
| API | Yes | — |
| Self-hosted | Yes | Yes |
| Plans published | 2 | 0 |
| Spec score · Mail Server Software | 8.3 (#6) | 7.2 (#30) |
| Deployment | The Enterprise Edition is an on-premises product that keeps data on the user's own server. | Postfix is built from source and runs on UNIX-like systems; operating-system and appliance vendors also distribute ready-to-run versions. |
| Purpose | iRedMail is open-source software for deploying a full-featured mail server. | Postfix aims to be fast, easy to administer, and secure. |
| Support | Enterprise Edition pricing includes technical support; general technical questions and issues can also be posted to the online forum. | The postfix-users mailing list is for questions, problem reports, and feature requests; non-member postings are silently discarded. |