Client (Blockchain)

A blockchain client is the software that lets a computer take part in a blockchain network as a node. It downloads blocks, checks that each transaction and block follows the protocol's rules, keeps a copy of the ledger or part of it, and relays data to other nodes. A full node client verifies everything itself, while a light client checks only block headers and relies on full nodes for details. Bitcoin's reference client is Bitcoin Core; Ethereum has several independent clients, and since 2022 each Ethereum node runs both an execution client and a consensus layer client. Having several clients written by different teams, known as client diversity, reduces the risk that a single software bug halts or splits the network. Also see Different Types of Blockchain Nodes.