Offline sync, federation, and merge conflicts

How offline queues, Matrix bridges, and merge-conflict UI fit together in FluxyChat.

Offline sync, Matrix federation, and merge conflicts are related problems. FluxyChat handles them as one story instead of three disconnected features.

The loop

sequenceDiagram
  participant Client
  participant DO as Room DO
  participant D1
  participant Matrix

  Client->>Client: IndexedDB outbox while offline
  Client->>DO: reconnect and delta sync (syncStatus)
  DO->>D1: authoritative messages
  Note over Client: If two edits collide, open merge-conflict UI
  Client->>DO: resolve keep_a / keep_b / merge_both
  DO->>Matrix: optional outbound bridge

Pieces

Layer	What	Where
Offline-first	WS events, pending send queue, `syncStatus`	`@fluxy-chat/sdk`, React Native outbox
Authoritative room	Durable Object and D1 history	Worker Room DO
Conflict UI	Side-by-side resolve when edits diverge	Merge conflicts
Federation	Matrix appservice bridge in and out	Bridge routes and docs

Operator checklist

Enable offline-first in the SDK (offlineFirst: true, default on web).
Show a connection banner when syncStatus is offline or pending.
Wire MergeConflictPanel (or your own UI) on deliveryConflict and the pending merge API.
For multi-org Matrix, configure the bridge and verify inbound traffic with the webhook emulator suite.

How this compares

Capability	Stream-style	Matrix-only	FluxyChat
Offline queue	SDK local cache	Client cache	IndexedDB or RN outbox plus `syncStatus`
Conflict UX	Usually last-write-wins	Room state	Explicit merge panel
Federation	Limited	Native	Optional Matrix bridge