hMailServer

Spec sheet

Purpose

hMailServer is a self-hosted mail server that supports SMTP, IMAP and POP3.Read 12 Oct 2026 · gitlab.com

Intended users

The documentation suggests hMailServer for small businesses, developers needing an SMTP and IMAP test endpoint, and hosting providers.Read 12 Oct 2026 · hmailserver.co.uk

Support

Free help is available on the community forum, where answers are not gated behind a support plan.Read 12 Oct 2026 · hmailserver.co.uk

Databases

Windows supports SQL Server Compact, MySQL or MariaDB, Microsoft SQL Server and PostgreSQL; Linux supports PostgreSQL and MySQL or MariaDB.Read 12 Oct 2026 · hmailserver.co.uk

Directories and calendars

It serves account address books over CardDAV and calendars over CalDAV when the web services HTTPS listener is enabled.Read 12 Oct 2026 · hmailserver.co.uk

Download verification

The FAQ says release files have Sigstore bundles, Linux SHA-256 checksums and Windows Authenticode signature verification instructions.Read 12 Oct 2026 · hmailserver.co.uk

Email authentication

It supports SPF, DKIM, DMARC, MTA-STS, DANE, ARC sealing and TLS reporting.Read 12 Oct 2026 · hmailserver.co.uk

Linux limitations

Linux has no Control Panel, COM API or Microsoft SQL Server support, and moving an existing Windows installation to Linux is not a supported migration.Read 12 Oct 2026 · hmailserver.co.uk

Mail protocols

It serves mail to clients such as Outlook, Thunderbird and Apple Mail, or through its built-in webmail.Read 12 Oct 2026 · hmailserver.co.uk

Not an Exchange replacement

The FAQ says hMailServer has no Teams integration or ActiveSync and is not a replacement for Microsoft Exchange.Read 12 Oct 2026 · hmailserver.co.uk

REST API

The REST API is available on Windows and Linux but is off by default; it requires a TLS certificate and key to bind beyond loopback.Read 12 Oct 2026 · hmailserver.co.uk

Security updates

The FAQ says release 6.3.6 fixes security flaws found in earlier versions and that the 6.3 line receives security fixes until 30 September 2027.Read 12 Oct 2026 · hmailserver.co.uk

Spam and virus filtering

It provides spam filtering, virus scanning through ClamAV, a rules engine and Sieve filtering.Read 12 Oct 2026 · hmailserver.co.uk

Webmail

It includes built-in webmail at `/portal` on Windows and Linux, enabled through the REST API listener.Read 12 Oct 2026 · hmailserver.co.uk

Plans and prices

Every hMailServer plan and price →

Where Specifiction places it

• Mail Server Software#10 of 348.0