Sync model

The TypeScript sync manager (@omnichat/client) owns local persistence, optimistic sends, and reconnect catch-up.

Goals

• Optimistic UI with stable client_msg_id
• Persist rooms/messages/receipts on device
• Retry unacked sends with backoff
• Catch up via SyncRoom / since_seq

Packages

Package	Role
@omnichat/client	Sync engine + MemoryStorage + IndexedDBStorage
@omnichat/storage-sqlite	SQLite adapter for React Native / Expo
@omnichat/react	Hooks shared by React web and React Native

Local schema (logical)

• rooms — room_id, since_seq (cursor), joined
• messages — keyed by (room_id, client_msg_id); optional server_msg_id / seq; status = pending | confirmed | failed
• receipts — (room_id, user_id) → last_read_seq (monotonic max)
• outbox — unacked sends with attempts + next_attempt_at_unix_ms

Reconnect loop

1. Open WebSocket → Auth → AuthOK
2. For each joined room: JoinRoom → SyncRoom(since_seq) until !has_more
3. Flush outbox (same client_msg_id, exponential backoff)
4. Apply live MessageEvent / receipts with dedupe

Conflict rules

• Dedupe by server_msg_id or (room_id, client_msg_id)
• Receipts are monotonic (max of local/remote)
• Future edit/delete: server wins

Storage adapters

// Web
import { createOmniChat, createIndexedDBStorage } from '@omnichat/client';

// React Native / Expo
import { createSqliteStorage } from '@omnichat/storage-sqlite';
import * as SQLite from 'expo-sqlite';
const storage = await createSqliteStorage(SQLite.openDatabaseAsync);

Wire protocol details: Protocol. SDK usage: SDK guide.