A validator is a node that proposes and verifies new blocks on a Proof of Stake blockchain. In Proof of Work systems, miners compete to solve puzzles. In Proof of Stake, validators stake tokens as collateral. They're selected to propose blocks based on their stake. Other validators attest to the block's validity. If everything checks out, the block is added.
If a validator misbehaves, proposes an invalid block or attests to invalid blocks, they lose their staked tokens. This slashing is the punishment mechanism. It makes attacks expensive. Running a validator requires maintaining a node, handling tokens, and understanding the protocol. On Ethereum, validators needed 32 ETH to participate. Solo staking is increasingly difficult.
Most validators participate through staking pools where multiple users pool their tokens. This creates centralization risk. If a few large pools control most staking power, they control the network. But it's necessary for meaningful validator participation. Validators earn rewards for securing the network, new token issuance plus transaction fees. This creates incentive alignment.
Validators profit when the network thrives. They lose tokens when they misbehave. Validators are the backbone of Proof of Stake consensus.
Interactive Visualizer
Proof of Stake Validator
Interactive simulation of validator selection, block proposal, and consensus
How it works: Validators are selected based on stake weight. The selected validator proposes a block. Other validators attest to its validity. If 67% attest to a valid block, it's finalized and rewards are distributed.
Slashing: Validators who propose or attest to invalid blocks lose stake and can be banned. Click validators during attestation phase to make them attest.