Validator

A validator is a participant in a proof-of-stake blockchain that locks up collateral in order to help produce and confirm blocks. Validators are selected by the protocol to propose new blocks and to attest that the blocks proposed by others are valid. On Ethereum, activating a validator requires staking 32 ETH into the deposit contract. Correct participation earns rewards; being offline or acting dishonestly incurs penalties.

Why it matters

Validators are the security backbone of proof-of-stake networks. Their staked collateral is what makes their votes on the state of the chain trustworthy, because dishonest behaviour can be punished by slashing, which destroys part of the stake. An attacker would need to control a very large share of total stake and would risk losing it, making attacks economically irrational when stake is widely distributed. Validators also perform routine duties, proposing blocks when selected and attesting to others, so consistent uptime and correct configuration are as important to their rewards as the size of the stake itself.

Common misunderstanding

Because staking pays rewards, becoming a validator is often treated as free money. In fact validators must keep hardware online and correctly configured, and mistakes such as running the same keys on two machines can trigger slashing. Many users instead delegate to staking services, which introduces its own trust and custody considerations, since you rely on the operator to run infrastructure honestly and, in some arrangements, to hold your assets.

Related terms

See proof of stake, node, consensus mechanism and multi-signature wallet.