Cyrus IMAP
Cyrus IMAP: A mature, scalable choice for organizations managing their own IMAP infrastructure. Ranked #27 of 34 in Mail Server Software by our editors (6.5/10); pricing: Free plan; best for mature, scalable IMAP infrastructure.
At a glance
- Editor score6.5 / 10
- PricingFree plan
- Best forMature, scalable IMAP infrastructure
- Free planYes
- Paid fromNone
- License modelOpen-source
- Founded1993
- Facts checked21 Sep 2026
Where it wins
- Supports IMAP, POP3, JMAP, CalDAV, and CardDAV access
- Includes quotas, ACLs, Sieve filtering, replication, and clustering
- Handles SPF, DKIM, DMARC, antivirus, and antispam tool support
Where it doesn't
- Requires Linux infrastructure managed by the operator
- Does not provide a webmail interface
- Cyrus Murder is not a true high-availability solution
Our verdict on Cyrus IMAP
Cyrus IMAP is open-source server software for organizations that need to manage email, contacts, and calendars on their own infrastructure. It supports mailbox access through IMAP, IMAPS, POP3, POP3S, and JMAP, while CalDAV and CardDAV extend the platform to calendars and contacts. The project began development in 1993 and is designed for deployments ranging from small installations to large enterprise environments. Its strongest fit is for teams that want mature, self-hosted mail infrastructure rather than a hosted mailbox service or a packaged webmail product.
The feature set is broad for a mail server. Server-side filtering uses Sieve, while mailbox quotas and access-control lists provide operational controls for storage and permissions. Replication between Cyrus servers supports distributed deployments, and Cyrus Murder aggregates clustered servers through clustered and redundant frontends. The platform also supports antivirus and antispam tool integration, along with SPF, DKIM, and DMARC handling. JMAP, CalDAV, and CardDAV make it relevant when email needs to coexist with modern clients and shared calendar or contact workflows.
Cyrus IMAP is free open-source software for Linux and self-hosted environments, so the main consideration is operational ownership. The operator is responsible for deployment, administration, infrastructure, and the surrounding client experience. Organizations seeking a webmail interface included with the mail server should choose an alternative or add a separate interface. Cyrus Murder can help organize clustered frontends, but it should not be treated as a complete high-availability or redundancy solution. Choose Cyrus IMAP when protocol coverage, policy controls, replication, and long-term maturity matter most; look elsewhere when a managed service or integrated webmail experience is the priority.
Your product? Our editors can test Cyrus IMAP in depth and publish a review, labelled as paid · from $99/mo →
Cyrus IMAP pricing
Cyrus IMAP fact sheet
| Free plan | Yes |
|---|---|
| Paid from | None |
| License model | Open-source |
| Webmail interface | No |
| IMAP/POP3 access | Yes |
| Mobile sync | Not verified |
| Antispam tools | Yes |
| Mailbox limit | Not verified |
| High availability | Yes |
| Deployment | Self-hosted |
| Platforms | Linux |
| Support | Community, Docs |
| Built for | Small business, Mid-market, Enterprise (editorial estimate) |
| Pricing | Free plan |
| Website | cyrusimap.org |
| Facts checked | 21 Sep 2026 |
Alternatives to Cyrus IMAP
- Microsoft Exchange OnlineA Microsoft-centric hosted mailbox service with Outlook, archiving, compliance, and migration tools.9.3
- Zimbra CollaborationA broad open-source suite for organizations that need email, collaboration, and deployment control.9.1
- IceWarpA broad hosted email suite with collaboration, migration tools, and self-hosted deployment.9.0
See all Cyrus IMAP alternatives →
Used Cyrus IMAP? Be the first to review it
The editor score above is our own research. What this page doesn't have yet is a reader's view — what you used Cyrus IMAP for, what worked and what didn't. No stars are seeded and no review is paid for; an editor reads every one before it appears.
Write a reviewTwo minutes · verified accounts only · read by an editor before it appears
Featured on iTechGuides
Cyrus IMAP is listed in our Mail Server Software directory. Add the badge to your site — it links back to this page.
<a href="https://www.itechguides.com/products/cyrus-imap/"><img src="https://www.itechguides.com/best/badge/cyrus-imap.svg" alt="Featured on iTechGuides" width="230" height="46"></a>
Guides on mail server software
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. How we rank.
Last updated · How we research and update