Hermes Mail Suite

In Greek myth, Hermes was the messenger of the gods - the one who carried words between worlds, faster than anyone, on winged sandals. He was the patron of travelers, communication, and swift, reliable delivery: the original courier. That's exactly the job an email server does, thousands of times a second - pick up a message, find the right destination, and get it there quickly and intact. The name is a nod to that lineage: speed, trust, and the simple, ancient art of delivering a message to whom it's meant for. Lightweight on its feet, never weighed down - fitting for a mail server that does the whole job in a handful of megabytes.

A complete mail server in a few megabytes

Most self-hosted email is a pile of moving parts: one tool for SMTP, another for IMAP, another for spam, more for DKIM and antivirus. Hermes replaces the whole pile with one privilege-separated daemon whose only dependency is OpenSSL.

What you get

• 📨 Everything in one ~10 MB binary: inbound SMTP, authenticated submission, IMAP, Sieve, DKIM/SPF/DMARC, DANE/MTA-STS, anti-spam, and antivirus.
• 🪶 Runs in under 100 MB: the entire stack, idling, fits in less RAM than a browser tab. Deploy it on the cheapest VPS you've got.
• ⚡ Fast by design: a single event loop per service, no thread-per-connection bloat, DNS-heavy checks offloaded so nothing blocks.
• 🔒 Secure by architecture: every service drops privileges and runs in a seccomp sandbox. A compromised parser can't reach your keys or your system.
• 🧠 Smart filtering built in: greylisting, RBL/URIBL, Bayesian scoring, and a native hash-based antivirus that catches known malware without ClamAV's gigabyte footprint.

Why it's different

We didn't glue five projects together - we built one, from scratch, small enough to read end to end. The signature database loads once and is shared across every process with zero extra memory. The spam engine is honest about forwarded mail. The antivirus auto-updates with no cron to babysit. It just runs.

Where it's headed

Our latest release v0.1.7 sharpened the core: correct DMARC on forwarded mail, shared-memory antivirus, outbound abuse containment, and per-flow logging that actually tells you what's happening.

Next up: broader threat coverage and even tighter operational polish.