What this module covers
- What Ethereum validators do
- Execution vs Consensus layers
- Validator duties and rewards
- High level overview of penalties, downtime, and slashing
Ethereum validator basics
An Ethereum validator is responsible for:
- Proposing blocks (happens every 1-2 months, depends on active validator count)
- Attesting to blocks (happens once per epoch, or every ~6.4 mins)
- Staying online and in sync with the network
Validators are rewarded for correct behavior and penalized for downtime or incorrect actions.
Execution vs Consensus layers
Running a validator requires two clients:
- Execution Layer (EL)
- Executes transactions and smart contracts
- Examples: Geth, Nethermind, Besu, Erigon
- Consensus Layer (CL)
- Handles validator duties and consensus
- Examples: Lighthouse, Prysm, Teku, Nimbus
These clients communicate locally and must remain in sync for correct operation.
Validator duties
- Attesting
- Voting on the validity of blocks
- Main source of steady rewards
- Proposing
- Creating a block when selected
- Higher reward, but rarer
- Sync committee participation
- Serving light clients by signing block headers
- Assigned for long periods (~27 hours per committee)
- Small but consistent rewards while assigned
Good performance requires:
- Stable uptime
- Low latency
- Correct client configuration
Rewards, penalties, and slashing
- Rewards come from correct proposals and attestations
- Penalties occur when a validator is offline or late
- Slashing is rare but severe, and happens when:
- Signing conflicting messages
- Running the same validator keys in multiple places
You will not be slashed for normal mistakes, but poor operational practices increase risk.
What is client diversity?
Ethereum relies on client diversity to reduce systemic risk.
Running a minority client combination helps the network and is encouraged.
You can check current diversity stats in:
- https://clientdiversity.org/
Read more here
- Nodes and clients https://ethereum.org/developers/docs/nodes-and-clients/
- Proof-of-stake rewards and penalties (incl. slashing) https://ethereum.org/developers/docs/consensus-mechanisms/pos/rewards-and-penalties/
- Ethereum staking overview https://ethereum.org/staking/
End of the module
You’re done with this module when you can confidently answer:
What does a validator actually do?
What is the difference between EL and CL?
Why do validators get penalized or slashed?
Why does client diversity matter?