- Fast first paint: conversations can hydrate from local cache before the network round-trip completes when the user has visited before.
- Consistent ordering: messages appear in one timeline order across devices at the product level.
- Resilience: transient network failures retry; obvious failures surface in UI rather than silent drop.
This document avoids implementation identifiers (storage backends, internal metrics). Treat the platform as a black box with the behaviors above.
Show sent messages immediately in your UI, then reconcile when the server timeline confirms or corrects order. On reconnect, fetch delta/history and merge into local state — same pattern as modern local-first chat apps.
Concurrent edits to mutable fields are merged on the client so rapid multi-device typing does not corrupt thread state; the server relays updates rather than acting as a manual merge authority for those planes.
Private mobile/browser notifications use Web Push when enabled; in-app live updates use the active session path. See ../publication context — Web Push article on the main docs repo for narrative detail.