Cryptxt is the encrypted messenger you host yourself — private chat, voice and video with post-quantum crypto, anonymous IDs and an encrypted SMS fallback for when the internet is off.
Signal asks you to trust Signal. WhatsApp asks you to trust Meta. Both encrypt the message and both still see who talked to whom, when, and from where. Cryptxt removes the third party entirely — the server in the message path is one you own.
Start anonymous with a cryptographic Cryptxt ID. Phone numbers are strictly optional and can be added later purely for SMS recovery — never as your handle, never as a discovery key you did not opt into.
PQXDH plus the Double Ratchet on every session, MLS group cryptography that scales past hundreds of members, and SFrame-encrypted calls. The primitives are vendored and review-gated rather than pulled fresh from a registry at build time.
The whole stack sits behind your own domain. Docker Compose gets a lab running in ten minutes, Helm handles production, and signed air-gap tarballs cover networks that never touch the internet at all.
An encrypted SMS fallback keeps the same keys and the same forward secrecy when data is blocked or throttled. Offline-first clients let you read, compose and verify with no signal at all, then sync when the link returns.
Every primitive below is a published, reviewed design. Cryptxt’s contribution is assembling them so that no server you do not own ever sits in the path.
Desktop gets a rail-and-workspace layout tuned for long sessions. Mobile gets a chat surface that reads at a glance. Every client shares one crypto core.
Pull the compose file, point it at your domain, let certbot issue the certificate. That is the whole first-run path — no sales call in front of it, no account to create.