What a validator does
In Proof of Stake, validators replace miners. Instead of competing to solve mathematical puzzles (Proof of Work), validators are chosen to propose new blocks based on the amount of crypto they've staked as collateral.
Their job is straightforward:
- Propose blocks. When selected, a validator bundles pending transactions into a new block and proposes it to the network.
- Attest to blocks. Other validators verify the proposed block and "attest" that it's valid — the transactions are legitimate, the state transitions are correct.
- Stay online. Validators need to be consistently available. Going offline means missing attestation duties and losing rewards (or being penalized).
The economics
Validators earn rewards for performing their duties correctly:
- Block proposal rewards — earned when selected to propose a block
- Attestation rewards — earned for correctly voting on blocks proposed by others
- Sync committee rewards — earned when randomly selected for the sync committee
- Priority fees (tips) — paid by users for faster transaction inclusion
- MEV — additional income from transaction ordering optimization
On Ethereum, running a solo validator with 32 ETH typically earns 3-5% APY from all these sources combined.
Validator selection
Validators are chosen pseudo-randomly to propose blocks, but the probability is weighted by stake. A validator with 32 ETH has the same chance per unit as anyone else — but someone running 10 validators (320 ETH) gets 10× the proposing opportunities.
This is by design: more stake means more skin in the game, which means more trustworthy behavior (at least in theory).
What goes wrong
- Going offline. Validators that miss attestations lose a small amount of rewards. Extended downtime (days) incurs increasing penalties.
- Double voting. If a validator signs two different blocks for the same slot, it's slashed — a significant portion of its stake is destroyed.
- Surround voting. If a validator makes contradictory attestations, it's also slashed.
- Correlated failures. If many validators fail simultaneously (e.g., a cloud provider goes down), penalties are amplified. This incentivizes infrastructure diversity.
Delegation
Most people don't run validators themselves. Instead, they delegate:
- On Solana, Cosmos, Polkadot: You delegate tokens directly to a validator and share in their rewards.
- On Ethereum: Solo staking requires 32 ETH and technical knowledge. Most users go through liquid staking protocols (Lido, Rocket Pool) which handle validator operations.
Why this matters for traders
Understanding validators helps you evaluate staking yield claims, assess network security, and understand why some chains are considered more decentralized than others. It's also useful context for understanding staking-related token economics.
Before getting into staking or delegating, build your understanding of crypto market mechanics on Korvex — where you can practice trading ETH, SOL, and other PoS assets with zero risk.