Definition
A validator is a network role in certain blockchain consensus mechanisms responsible for verifying transactions, proposing or attesting to new blocks, and helping determine the canonical state of the ledger. Validators typically operate full nodes, maintain a copy of the blockchain, and participate in consensus by following protocol-defined rules that govern block validation, finality, and network security.
In Simple Terms
A validator is a participant in a blockchain network that checks transactions and blocks to help decide which data is officially accepted on the chain. By running specialized software and following the protocol’s rules, validators contribute to keeping the blockchain accurate, consistent, and resistant to invalid data.
Context and Usage
The term validator is most commonly used in proof-of-stake and related consensus designs to distinguish these participants from miners in proof-of-work systems. Discussions about validator sets often involve topics such as network decentralization, security assumptions, economic incentives, and data availability. The number, distribution, and behavior of validators are central to how a blockchain’s consensus and governance are characterized.