> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hypedexer.com/llms.txt
> Use this file to discover all available pages before exploring further.

# l4BookUpdates

> L4 book update events only (no full snapshot on this channel)

Subscribe with `{"method":"subscribe","subscription":{"type":"l4BookUpdates"}}`. Frames follow **`L4BookUpdate`** (same shape as incremental updates for **`l4Book`**).


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