Cyrus IMAP vs Postal
A side-by-side comparison of two self-hosted mail servers options — licensing, setup difficulty, resource needs, and what each one replaces.
Not the right match-up?
Cyrus IMAP
Scalable IMAP and POP server for large deployments
VS
Postal
Complete mail delivery platform for outgoing email
| Feature | Cyrus IMAP | Postal |
|---|---|---|
| Category | Mail Servers | Mail Servers |
| License | BSD-3-Clause | MIT |
| Language | C | Ruby |
| Setup difficulty | Hard | Hard |
| Min. RAM | 1,024 MB | 2,048 MB |
| Deployment | bare-metal, source | docker, bare-metal |
| GitHub stars | ★ 641 | ★ 16,724 |
| First released | 1994 | 2017 |
| Replaces | Microsoft Exchange | SendGrid, Mailgun, Postmark |
Why pick each one
Frequently asked questions
Is Cyrus IMAP or Postal better?
Neither is universally better. Postal has the larger community; both share a hard setup difficulty, so the decision comes down to features and licensing.
Are Cyrus IMAP and Postal free and open-source?
Yes. Cyrus IMAP is licensed under BSD-3-Clause and Postal under MIT. Both can be self-hosted at no software cost.
Can I run Cyrus IMAP and Postal with Docker?
Cyrus IMAP: check the project docs for container support. Postal: yes.