hMailServer review
A free, open-source Windows mail server for administrators who want control over email infrastructure.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
hMailServer is a free, open-source email server for organizations and administrators that want to operate their own mail infrastructure on Microsoft Windows. It runs as a Windows service and provides SMTP, IMAP, and POP3, with configurable domain and mailbox management. The feature set suits teams that need direct control over mail delivery, storage, filtering, and server administration rather than a hosted email service.
The product covers core mail-server operations in considerable detail. IMAP includes IDLE, SORT, Quota, and ACL extensions, while DKIM signing and verification support domain authentication. Filtering options include SPF, SURBL, DNS blacklists, greylisting, and score-based rules. Administrators can add ClamAV or a custom antivirus scanner, manage aliases, distribution lists, forwarding, and rules, and fetch messages from external POP3 accounts. MySQL, Microsoft SQL Server, and SQLite are supported, and the COM public API provides an automation path alongside the administrator GUI.
Its main trade-off is operational responsibility. hMailServer is built for a Windows deployment, so organizations choosing it should have administrators who can manage the server, databases, mail flow, filtering, and antivirus integrations. Storage, alias, and message-size limits are configurable, rather than organized as standard hosted-service allowances. The product also focuses on mail-server infrastructure: webmail, mobile access, and calendar functionality are not part of the documented feature set. Choose hMailServer when self-hosting, Windows administration, and configurable mail services are priorities; choose a hosted email product when browser, mobile, and broader collaboration access matter more.
hMailServer pros and cons
- Where it wins
- SMTP, IMAP, POP3, DKIM, filtering, and outbound mail delivery
- ClamAV integration plus SPF, SURBL, DNS blacklist, and greylisting
- Aliases, fetching, APIs, migration tools, and multiple database options
- Where it doesn't
- Windows-only server deployment limits platform flexibility
- Requires administrators to operate and maintain the mail infrastructure
- Does not provide verified webmail, mobile coverage, or calendar features
hMailServer fact sheet, pricing and score →
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