A validator is a network participant with a defined role in verifying and contributing to consensus on transactions, blocks, or ledger state.
The validator role depends on the protocol. In many proof-of-stake networks, validators propose blocks, attest to blocks proposed by others, or vote on checkpoints and finality. Validators must follow protocol rules and can receive rewards or penalties. Some networks use different terminology or assign validation functions to miners, committees, or other consensus participants.
A validator has a consensus-specific role. A node can participate in verification, storage, or relaying without necessarily having authority to propose or attest to blocks.
Validator incentives, concentration, uptime, and behavior influence the security and settlement properties of blockchain networks used by stablecoins.
A proof-of-stake validator can attest that a proposed block containing stablecoin transactions follows the network's consensus rules.