Blockchain Validator

Blockchain validators are network nodes on proof of stake (PoS) blockchains that process, validate, and add transaction blocks to a permanent blockchain ledger. It’s tempting to contrast the term validator with the miner, which serves a similar function on proof of work (PoW) blockchains.

Miners, however, while doing work such as processing and adding transaction blocks, additionally perform the work in PoW blockchains that grant them the right to add blocks. On PoS blockchains, this is split into two roles: stakes and validators. Stakers vote or post stakes in support of any node becoming a validator, and validators take on the role of adding blocks to the chain.

When users initiate blockchain transactions, those transactions are queued on the network, awaiting subsequent validation. Validator nodes then batch individual transactions in a block to verify them. Every blockchain has its own set of rules related to the total number of transactions per block. When a block is completed, validators process it, adding it to the blockchain as a permanent record.

A validator may choose which transactions to pair together to create a new block. This decision is usually dictated by what transaction fees they will receive for validating the transaction, not the order of submission. For example, when sending crypto assets, a sender includes transaction fees to incentivize potential validators. Senders choose their fee amount and can even send transactions without fees.

Transactions with very low or no fees are highly likely to be ignored by validators. As a result, they may remain unconfirmed for an indefinite period. If a transaction is not added to a block for validation, it could be dropped from the network. The overall process of block validation usually differs between PoW-based blockchains, including Bitcoin (BTC), Ethereum (ETH), Solana (SOL), and Ethereum 2.0.

Validation on Proof of Work Blockchains

On a PoW blockchain, miners vie to process blocks by solving complex computational puzzles. The process is highly competitive, and the first validator node that successfully solves the puzzle receives a reward.

Solving the computational puzzle requires significant computational and hash power and is a highly time- and energy-consuming exercise. Due to the massive number of blocks miners regularly validate on large PoW chains with the corresponding use of resources, PoW is often criticized for being harmful to the environment.