Evolu's offline-first sync protocol addresses six of eight common failure modes

Evolu is a local-first data framework that uses SQLite databases on each device, syncing changes through end-to-end encrypted relays. Its sync protocol handles six of eight common offline-first failure modes internally, moving more responsibility from the backend into the system design. The framework is notably transparent about two unsolved challenges: enforcing true, permanent data deletion across all devices and handling schema migrations. A key design choice uses client-supplied timestamps for reconciling changes, which allows a relay to operate without reading the encrypted data but introduces specific trade-offs.