40 Compute Units.
Over HTTPS, Hyperliquid Mainnet keeps roughly 165 days of blocks, receipts and logs; requests for older blocks return JSON-RPC error
-32603 with invalid block height. Over WebSocket the request is served by nanoreth, the HyperEVM archive client, and any block back to genesis is available.Reference: Here
Parameters
DATA, 32 Bytes - hash of a block
Returns
QUANTITY - integer of the number of transactions in this block.