What it is
Herkos Mail is a free, open-source mail client built on Nostr. Your Nostr key is your account. Messages between Nostr users are end-to-end encrypted by default, using NIP-17 gift wrap, and you can still write to ordinary email addresses through a bridge.
End-to-end encrypted between Nostr users. Custom folders that sync across your devices and survive a reinstall. Multiple identities from one key. Attachments on Blossom servers.
Calendar planned
A private agenda where every event is encrypted before it reaches a relay. Your calendar says more about you than your inbox does, so encryption is not optional.
Drive planned
Encrypted files on Blossom servers with a Nostr-signed index, replicated across several servers so that no single operator can lose your data.
How signing in works
There is nothing to register. You sign in with your nsec, or — better —
with a remote signer (a NIP-46 “bunker”, by QR or nostrconnect://),
in which case your secret key never touches the device at all. You can export your key
whenever you want, because it is yours.
Mail between Nostr users is end-to-end encrypted and nobody in between — us included — can read it. Mail to a Gmail or Outlook address is not: a bridge converts it and can see the content. Read state and folder names are, for now, public metadata on your relays. We would rather write that down than have you find out later — the privacy policy and the security page say exactly who can see what.
Built to be checked
All of it is open source under the MIT licence: one Flutter codebase for mobile, desktop and web, fully translated into 12 languages. The defaults — 5 relays, 5 DM relays, 5 Blossom servers, 2 bridges — are all editable, and none of them is run by us.