Why build it ourselves
Off-the-shelf sync libraries fell short on per-record permissions, field-level conflict resolution, and offline-first behavior on mobile.
Architecture
A central event log fans out through WebSocket subscriptions while each device keeps a local replica that applies events deterministically.
Backpressure matters more than raw throughput.
Schema migrations on replicated data need rehearsals.
Testing requires partitions, drops, and reordering.
