Conflict-free offline sync

Two devices hold their own replica of the same contact. Take one offline, edit both, then reconnect — they converge with no conflict dialog and no lost write. Edits to different fields both survive; edits to the same field are settled deterministically by a hybrid logical clock. Your changes persist across a page reload, so you can genuinely leave a device “offline” and come back.

✓ Replicas converged — identical state

Try this

  1. Take Device B offline.
  2. On A change phone; on B change email.
  3. Bring B back online → both edits survive. No conflict.
  4. Now go offline again and change the same field on both. On reconnect they agree on one value — deterministically, via the HLC stamps below each field.
  5. Offline, remove a tag on A and re-add the same tag on B. On sync the tag survives — that is add-wins OR-Set semantics.

Event log

No events yet — edit a device.

↔ Try real peer-to-peer across devices

Hand-rolled CRDT · hybrid logical clock · LWW field map · add-wins OR-Set · proven by a randomized convergence test suite