Ethereum (ETH) is a decentralized, open-source blockchain platform that enables developers to build and deploy smart contracts—self-executing agreements with the terms directly written into code. Launched in 2015 by Vitalik Buterin and a group of co-founders, Ethereum introduced a major innovation to blockchain technology by expanding its use beyond simple peer-to-peer transactions.

At the core of Ethereum is its native cryptocurrency, Ether (ETH), which is used to pay for transaction fees and computational services on the network. Ethereum serves as the foundation for thousands of decentralized applications (dApps) across a wide range of use cases, including finance (DeFi), gaming, NFTs (non-fungible tokens), identity, and supply chain management.

Ethereum transitioned from a proof-of-work (PoW) to a proof-of-stake (PoS) consensus mechanism in 2022 with the upgrade known as "The Merge". This shift significantly reduced its energy consumption and opened the door to future scalability improvements, including sharding.

As the leading smart contract platform, Ethereum is at the heart of the Web3 ecosystem, empowering developers to create decentralized and censorship-resistant applications while enabling users to interact directly with blockchain-based services.