Ethereum is an open-source, decentralized blockchain platform launched on July 30, 2015 by a founding group that included Vitalik Buterin, Gavin Wood, Joseph Lubin, Charles Hoskinson, and others. It is best known as the first general-purpose smart-contract platform — programmable on-chain logic, not just transferable tokens — and is the foundational settlement layer for most of the contemporary decentralized-finance, NFT, and Web3 application ecosystem.
The network's native cryptocurrency, ether (ETH), pays for computation and storage on the platform via gas fees. Ethereum executed The Merge on September 15, 2022, transitioning the network from energy-intensive proof-of-work to proof-of-stake consensus, which reduced its electricity consumption by roughly 99.95% and changed its issuance economics. The protocol is governed off-chain through Ethereum Improvement Proposals (EIPs) and a loose coalition of client developers, researchers, and the Switzerland-based Ethereum Foundation; the broader ecosystem now includes a large set of layer-2 scaling networks (Arbitrum, Optimism, Base, zkSync, Starknet, and others) built directly on top of Ethereum mainnet.