Proof of Stake (PoS) is a consensus mechanism in blockchain networks where validators are chosen to create and validate new blocks based on the number of coins they hold and are willing to "stake" as collateral. Unlike Proof of Work (PoW), which relies on computational power, PoS aims to achieve consensus and secure the network by incentivizing validators who have a vested interest in maintaining the integrity of the blockchain. Validators are rewarded with transaction fees rather than newly minted coins, promoting energy efficiency and scalability compared to PoW. PoS is gaining popularity for its potential to reduce the environmental impact of blockchain technologies while maintaining security and decentralization.