Courier Mail Server vs Cyrus IMAP
Courier Mail Server
courier-mta.orgCyrus IMAP
cyrusimap.orgSide by side
| Figure | Courier Mail Server | Cyrus IMAP |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Linux | Yes | Yes |
| Self-hosted | Yes | Yes |
| Plans published | 1 | 1 |
| Spec score · Mail Server Software | 8.5 (#1) | 7.9 (#16) |
| Authentication | Authentication options include PAM, LDAP, MySQL, and PostgreSQL, with PostgreSQL identified as beta on the features page. | Cyrus uses Cyrus SASL and supports multiple authentication options. |
| Download | The download page lists Courier 2.0.7, dated 02-Aug-2026, as a source code tarball containing the mail server, IMAP server, webmail server, and maildrop filter. | Cyrus is available as source tarballs or source from Git, and as packages for major distributions; distribution packages may not be up to date. |
| Filtering | Integrated mail filtering supports administrator-installed external filters and recipient-specified rules through maildrop. | It supports server-side email filtering through Sieve. |
| Integrations | The server can use LDAP, MySQL, or PostgreSQL-based authentication databases and supports LDAP-based mail routing. | The installation guide describes receiving mail from SMTP servers such as Sendmail, Postfix, and Exim through LMTP. |
| Security | Courier supports STARTTLS and SSL for ESMTP, IMAP, POP3, and webmail; its ESMTP client can require a certificate signed by a trusted root CA. | The feature documentation lists Kerberos, LDAP, and SQL authentication, access control, and a sealed system design. |
| Support | The site lists an unmoderated courier-users mailing list for questions, bug reports, and comments, plus a separate read-only announcement list. | The project points users to active mailing lists for help. |
Plans
In their own words
Courier Mail Server
Courier Mail Server has no write-up on Specifiction yet; its figures are above.
Cyrus IMAP
Cyrus IMAP has no write-up on Specifiction yet; its figures are above.