Hermes Secure Email Gateway
Hermes Secure Email Gateway: A capable open-source gateway for teams managing email security in their own environment. Ranked #26 of 34 in Email Security Gateways by our editors (6.7/10); pricing: Free plan · 30-day trial; best for open-source gateway users on a budget.
At a glance
- Editor score6.7 / 10
- PricingFree plan · 30-day trial
- Best forOpen-source gateway users on a budget
- Free planYes
- Outbound filteringYes
- Facts checked19 Sep 2026
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
Our verdict on Hermes Secure Email Gateway
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.
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Hermes Secure Email Gateway pricing
All 2 Hermes Secure Email Gateway plans and prices →
Hermes Secure Email Gateway fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Not verified |
| Outbound filtering | Yes |
| Impersonation protection | Not verified |
| Malware sandboxing | No |
| Deployment model | Gateway |
| Microsoft 365 support | Yes |
| Google Workspace support | Yes |
| Free trial | 30 days |
| Deployment | Self-hosted |
| Integrations | 7 integrations: Microsoft 365, Google Workspace, Exchange, Postfix, Nextcloud, LDAP … |
| Pricing | Free plan · 30-day trial (source) |
| Website | hermesseg.io |
| Facts checked | 19 Sep 2026 |
Hermes Secure Email Gateway integrations
Hermes Secure Email Gateway lists 7 integrations on its own site.
- Microsoft 365
- Google Workspace
- Exchange
- Postfix
- Nextcloud
- LDAP
- Active Directory
Alternatives to Hermes Secure Email Gateway
- Sublime SecurityA customizable email security platform with unusually broad protection in its free Core plan.9.4
- Sophos EmailA broad cloud gateway for Microsoft 365 and Google Workspace email protection.9.2
- Cloudflare Email SecurityA flexible email gateway for organizations needing layered inbound and outbound protection.9.0
See all Hermes Secure Email Gateway alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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