Overview
Proof of Stake, or PoS, is a consensus mechanism where validators are chosen to create blocks based on the amount of cryptocurrency they hold and are willing to stake. Instead of spending energy like proof of work, PoS secures the network through locked capital that can be penalized for misbehavior. Ethereum's transition to PoS in 2022 made it the dominant model for major blockchains.
How It Works
Validators lock up a minimum stake as collateral and are pseudorandomly selected to propose and attest to blocks, with selection weighted by stake. Rewards are issued for honest participation, and slashing removes part of the stake for violations such as double-signing or extended downtime. Because a validator's capital is at risk, the network is economically incentivized toward honest behavior without the energy cost of mining.
Why It Matters
PoS reduces energy consumption by orders of magnitude and lowers the hardware barrier to participation, though it requires capital. It also enables features like lower issuance and more flexible validator sets. Its security rests on the assumption that no single actor controls enough stake to overtake the network, and it introduces risks such as centralization through large staking providers and slashing for delegators.
Related Concepts
PoS is the foundation for Validators, Slashing, and Delegated Staking. It also supports Liquid Staking derivatives and the Restaking economy that reuses staked capital for additional services.