Validator

A validator is the proof-of-stake equivalent of a miner. It runs node software, holds a stake of the native coin, and takes turns proposing new blocks and attesting that other validators' blocks are valid. Validators earn rewards for doing this correctly and are penalized for being offline or acting dishonestly.

On Ethereum, each validator is backed by 32 ETH, and the network had over a million active validators by 2024, many of them operated by a smaller number of staking services. On Solana, there are a few thousand validators, each of which receives delegated stake from many holders. The number of validators and how stake is distributed among them are commonly used measures of decentralization.

Running a validator requires reliable hardware, a stable internet connection, and attention to software updates. Downtime costs small penalties; signing two conflicting blocks, which indicates either an attack or a misconfiguration, results in slashing and ejection from the validator set. Most individuals delegate or use a staking service rather than run their own.