Family Manager is free and open source. The app, the shared encryption core, and the sync server are all public — you can read exactly how the cryptography works, or host the whole thing yourself.

View the source on Codeberg

Inspect the crypto

The encryption lives in one small, readable core package: XChaCha20-Poly1305 for encryption, BLAKE2b for key derivation, BIP39 for the recovery phrase, all via the audited libsodium library. No custom cryptography, nothing hidden.

Self-host the sync server

The blind sync server is a single small binary, published as a Docker image: darktrees/blind-sync. Point the app at your own server URL and your encrypted data syncs through infrastructure you control — the server still can’t read any of it. Its source, Dockerfile and compose file are in the same repository as the apps.

Reminders and email are yours to switch on

The two features that involve the server beyond relaying ciphertext are both server capabilities, and both ship off. Reminders and push wake-ups need a VAPID key pair configured; if there isn’t one, the routes don’t exist and the app knows not to offer notifications. Emailed calendar invites need an SMTP relay and a from-address; without them the route is absent and the feature never appears. Self-host and it’s entirely your call which of the two, if either, your family gets — and whose mail server carries the invites.

License

Free and open source — see the LICENSE in the repository for the exact terms.