Mempool

The mempool is the in-memory set of valid, signed transactions a node has received but that have not yet been included in a block.

When a transaction is broadcast it lands in each node's mempool until a block producer selects it, usually favouring higher fees. Mempool contents are local and transient: different nodes see slightly different pending sets, and entries drop out on inclusion or replacement. Reading pending transactions helps with fee estimation and detecting inbound payments before confirmation, but pending data is never final. For settled results you query confirmed blocks and transaction receipts through the archive RPC.