In practice a validator is software running around the clock: a client connected to the network as a <a href="/glossary/node/">node</a>, holding a signing key, doing unglamorous duties on a schedule. Most of the time that means attesting — voting on what it believes the current head of the chain is. Occasionally it is selected to propose a block. Uptime matters, because a validator that is offline misses its duties and collects small penalties for each one.
The collateral is the point. Under <a href="/glossary/proof-of-stake/">proof of stake</a> the protocol selects proposers in a way weighted by how much is staked, and misbehaviour is punished by slashing: an offence like signing two conflicting blocks is provable from the chain itself, and the penalty is taken from the deposit. This risk deserves stating without softening, because the classic way people get slashed is not malice but a configuration mistake, typically running the same keys on two machines at once in an attempt to improve reliability.
Most people who stake never run one. Delegating to an operator, joining a pooled service or staking on an exchange all mean handing the duties to someone else, and with them your exposure to their fees, their uptime and, on a custodial platform, their solvency. Exit is not always instant either: protocols commonly queue withdrawals, so staked funds may be illiquid for a period you should check before committing.
One naming trap: "validator" is also used loosely for any node that checks the rules. A plain full node validates everything it sees, secures nothing but its owner's own view, holds no stake and earns nothing. Only the staked kind participates in <a href="/glossary/consensus/">consensus</a>.
Mining vs Staking, Explained
Key takeaways
- Stake functions as collateral: rewards flow for correct behaviour, and slashing takes coins for provable misbehaviour.
- Being offline is usually a mild penalty, while running duplicate signing keys is one of the fastest ways to get slashed.
- Delegating or staking through an exchange swaps hardware and uptime risk for counterparty risk.
Validator — frequently asked questions
Do I have to run a validator to earn staking rewards?
No. You can delegate to an operator or use a staking service, and on many networks that is what most participants do. The trade-off is that you inherit the operator's fees, their uptime record and their operational mistakes, and on a custodial platform you no longer hold the coins yourself. Running your own gives you control and the full reward, at the cost of real responsibility for keys and availability.
Can I actually lose my staked coins?
Yes, in two distinct ways. Slashing removes part of your deposit for provable protocol offences such as signing conflicting blocks, and it does not care whether the cause was dishonesty or a misconfigured backup server. Separately, if you stake through a third party, that party can fail, be hacked or freeze withdrawals. Neither risk is theoretical, so read the slashing rules and the custody arrangement before you stake.
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