Validators - Blockchain Primitive Explained

What are Validators?

Validators are specialized nodes in Proof of Stake blockchains that verify transactions, propose new blocks, and participate in consensus. They’re the PoS equivalent of Bitcoin miners—responsible for securing the network and maintaining the blockchain. Unlike miners who compete with computational power, validators stake tokens as collateral and risk losing them if they misbehave.

Validator Responsibilities

Block Production

Creating new blocks:

Selected to propose blocks
Order transactions
Execute state transitions
Sign and broadcast blocks

Attestation

Validating others’ work:

Verify proposed blocks
Vote on validity
Participate in consensus
Contribute to finality

Network Maintenance

Infrastructure duties:

Maintain high uptime
Stay synchronized
Process transactions quickly
Store blockchain data

How Validators Work

Selection Process

Who produces blocks:

Stake-weighted random selection
More stake = higher chance
Algorithm varies by chain
Prevents prediction/manipulation

Consensus Participation

Reaching agreement:

Vote on proposed blocks
Follow consensus protocol
BFT voting rounds
Finality through supermajority

Reward Distribution

Earning for work:

Block proposal rewards
Attestation rewards
Transaction fees/tips
MEV opportunities

Becoming a Validator

Requirements

Typical needs:

Minimum stake (32 ETH, varies by chain)
Server infrastructure
Technical knowledge
Consistent uptime

Hardware Requirements

Infrastructure:

Dedicated server/VPS
Fast SSD storage
Reliable internet
Backup systems

Software

Running validator:

Client software
Key management
Monitoring tools
Update maintenance

Validator Economics

Rewards

Income sources:

Protocol inflation rewards
Transaction fees
MEV (Maximal Extractable Value)
Priority tips

Costs

Expenses:

Hardware/hosting
Electricity
Maintenance time
Opportunity cost of stake

Profitability

Calculation:

Rewards - costs = profit
Varies by network
Stake size matters
Competition affects returns

Slashing

What Gets Slashed

Punishable offenses:

Double signing: Validating conflicting blocks
Surround voting: Conflicting attestations
Extended downtime: Some chains penalize
Protocol violations: Chain-specific rules

Slashing Severity

Penalty ranges:

Minor: Small percentage of stake
Major: Large portion of stake
Severe: Complete stake loss
Correlation penalties: Worse if many slash

Prevention

Avoiding slashing:

Never run duplicate validators
Proper key management
Redundancy without duplication
Monitoring and alerts

Validator Types

Solo Validators

Individual operators:

Control own stake
Full rewards
Full responsibility
Technical expertise required

Institutional Validators

Professional operators:

Large stake holdings
Enterprise infrastructure
Multiple networks
Delegation services

Staking Pools

Shared validation:

Aggregate small stakes
Professional operation
Distributed rewards
Lower barriers

Validator Metrics

Performance Indicators

What matters:

Uptime: Availability percentage
Attestation Rate: Votes made vs. expected
Proposal Success: Blocks successfully proposed
Latency: Speed of responses

Reputation

Building trust:

Historical performance
Self-stake amount
Community involvement
Transparency

Validator Networks by Chain

Ethereum

~900,000 validators:

32 ETH minimum
Anyone can validate
Distributed validator technology emerging
Highly decentralized

Solana

~2,000 validators:

No minimum (economic pressure)
High hardware requirements
More centralized
Performance focused

Cosmos

Varies by chain:

Typically 100-200 active
Governance participation
IBC relaying
Chain-specific economics

Polkadot

297 elected validators:

NPoS selection
Nominators back validators
Shared security
Era-based rewards

Centralization Concerns

Risks

Concentration problems:

Exchange staking dominance
Geographic centralization
Client software monoculture
Economic barriers

Mitigation

Decentralization efforts:

Lower minimums
Delegation programs
Client diversity incentives
Geographic distribution rewards

The Future of Validators

Distributed Validators (DVT)

Key splitting:

Multiple parties hold key shares
No single point of failure
SSV Network, Obol leading
Improves resilience

Restaking

Expanded security:

Validators secure multiple networks
EigenLayer pioneering
Additional rewards
New risk considerations

MEV Solutions

Evolving landscape:

Proposer-builder separation
MEV-boost
Fair ordering research
Validator influence changing

Conclusion

Validators are the backbone of Proof of Stake networks, replacing the energy-intensive mining of PoW with capital-efficient staking. Understanding validator economics, responsibilities, and risks is essential for anyone running validators, delegating stake, or building on PoS networks. As the technology evolves with innovations like distributed validators and restaking, the validator landscape continues to mature.