# StreamL4Book

> 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>


# Stream L4 book

`StreamL4Book` is under evaluation.

Consumers wanting order-level book data should use [StreamL4BookUpdates](/docs/chains/hypercore-grpc/api-reference/stream-l4-book-updates), which provides typed per-order diffs across multiple markets with queue-position information. This is ideal for consumers that need order-level book data.