What is validator?

A participant in a proof of stake network that proposes and attests to blocks and is paid for doing so honestly.

A validator is not a person or a company. It is a stake position plus a signing key plus software that must be online, and one operator may run thousands of them. That distinction matters when you read that a network has a million validators: it says something about stake distribution, and much less about how many independent parties there are.

The misunderstanding worth correcting is that validators verify transactions in a discretionary sense. They do not judge anything. They run consensus rules and are penalized for deviating from them.

How it works

The role has two parts on Ethereum. In most slots a validator attests, signing a vote about what it sees as the head of the chain. Occasionally it is selected to propose, meaning it builds the block itself. Rewards come from performing both duties promptly and correctly.

Entry requires a stake deposit. Ethereum's staking documentation puts the requirement at 32 ETH for a validator to operate directly, which is why the majority of holders reach staking through an exchange or a pool rather than by running one. That threshold is also the reason the liquid staking token category exists.

Penalties come in two grades. Being offline costs roughly what you would have earned by being online, a slow leak rather than a catastrophe. slashing is the severe case, reserved for provable equivocation such as signing two conflicting blocks, and it removes a portion of the stake and ejects the validator. The Ethereum consensus specifications define the offenses precisely, and the point of the design is that honest downtime and dishonest signing are treated very differently.

Exiting is not immediate. A validator joins an exit queue whose length depends on how many others are leaving, and the stake is not withdrawable until the exit completes.

Example

Illustrative. A validator with 32 ETH staked at an annual rate of 3 percent earns about 0.96 ETH a year, or roughly 0.0026 ETH a day.

Go offline for a day and the loss is approximately what that day would have paid, so about 0.0026 ETH plus the missed rewards themselves. Annoying, recoverable. Get slashed for signing conflicting blocks and the penalty is a portion of the 32 ETH principal along with forced exit, which is a different order of magnitude entirely. Staking through a provider does not remove either risk; it transfers the operational responsibility while leaving you exposed to the consequences.

Why it matters when you buy

Most people meet validators through a staking product rather than by running one, and the question there is who operates the validator and what happens if it misbehaves. The yield pages show which exchanges offer staking for each asset and where it is available, and the guide on staking for beginners covers the tradeoffs between exchange staking, pooled staking, and running your own.

Related terms

• proof of stake: the consensus validators secure
• staking: how holders participate without operating one
• slashing: the penalty for provable misbehavior
• exit queue: the wait to withdraw stake
• block proposer: the validator selected to build a block
• withdrawal credentials: where the stake returns to

Questions

Do I need 32 ETH to stake Ethereum?

Not to stake, only to run a validator yourself. Exchanges and pooled staking services accept far smaller amounts by aggregating deposits, in exchange for a commission and a counterparty relationship.

Can I lose my stake by staking through an exchange?

Slashing risk exists wherever the validator is operated, and whether the exchange passes that loss to you is set by its terms. The larger exposure is usually the exchange itself, since the stake sits with a custodian.

How many validators does a network need?

There is no fixed number. What matters is how much stake is controlled by how few independent operators, since concentration rather than validator count is what determines whether a network can be coerced.