Hermes Secure Email Gateway review
A capable open-source gateway for teams managing email security in their own environment.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Hermes Secure Email Gateway is an open-source, self-hosted platform for organizations that want to filter inbound and outbound email under their own control. Its Community Edition combines anti-spam and anti-malware scanning with SPF, DKIM, DMARC and ARC processing, encryption, quarantine, message search and release workflows. It can operate as a gateway, a complete mail server or in hybrid mode, making it relevant for teams using Microsoft 365, Google Workspace, Exchange or Postfix.
The product’s strongest fit is its breadth of mail-security controls in the free Community Edition. It supports S/MIME, PGP, TLS and encrypted-PDF email protection, along with DMARC enforcement and report aggregation. Docker Compose deployment is available in gateway, full mail server and hybrid modes. Integration options also include Nextcloud, LDAP and Active Directory, giving administrators several ways to connect Hermes with an existing mail environment. Time-of-click URL protection through Link Guard is listed as a Pro feature rather than part of the Community Edition.
Pro adds per-server licensing, Link Guard, email disclaimers, organizational signatures, an intrusion prevention UI and a console firewall UI. Those additions are aimed at organizations needing more administrative and policy controls around the gateway. Hermes is less suitable for teams seeking a fully managed service or vendor-run sandboxing, since its published approach does not include a vendor-run sandbox farm. Choose it when self-hosting, open-source access and layered filtering matter; consider an alternative when delegated operations or managed sandbox analysis is central to the buying decision.
Hermes Secure Email Gateway pros and cons
- Where it wins
- Free Community Edition covers inbound and outbound filtering
- Supports SPF, DKIM, DMARC, ARC and multiple encryption methods
- Works with Microsoft 365, Google Workspace, Exchange and Postfix
- Where it doesn't
- Self-hosted deployment requires infrastructure management
- Pro licensing is per server rather than per user
- No vendor-run malware sandbox farm is included
Hermes Secure Email Gateway fact sheet, pricing and score →
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