Designing Resumable Websockets

Reconnecting a WebSocket is easy. Recovering the stream without losing, duplicating, or reordering data is the real problem.

Drawing from a production live-transcription system, this talk builds the server-side protocol for resilient real-time AI: logical sessions that outlive connections, heartbeats, sequence numbers, acknowledgements, replay buffers, idempotent processing, backpressure, and observability.

We will break the network on purpose, reconnect, and watch the backend restore the stream correctly.