# Replay and recovery

> HyperCore private-preview documentation.

> For the complete documentation index, see [llms.txt](/docs/llms.txt).

<Callout intent="info">
  This API is in private preview. Target September 2026; timing is subject to change.
</Callout>


# Replay and recovery

For the sequencing and recovery model, see [timestamps, cursors, and replay](/docs/data/hypercore/concepts/timestamps-cursors-and-replay).

1. Persist the cursor after processing each message on a replay-capable stream.
2. On disconnect, reconnect with exponential backoff and jitter.
3. Resubscribe, supplying the last persisted cursor in each replay-capable subscription object. Complete-snapshot streams resubscribe without a cursor.
4. Deduplicate overlapping messages using the identity documented for that stream — per-market sequence for book diffs, block height or round for block streams, and the event identity fields where a stream provides them.
5. For stateful snapshot-and-diff streams, a message with `isSnapshot: true` replaces local state for that market.