Ethereum (ETH) is a programmable blockchain platform, launched in July 2015 by Vitalik Buterin and co-founders, that introduced general-purpose smart contracts to crypto. Where Bitcoin focuses on storing and transferring value, Ethereum lets developers deploy autonomous programs — DeFi, NFTs, DAOs, stablecoins, on-chain identity — that execute on the Ethereum Virtual Machine (EVM).
Since The Merge (September 2022), Ethereum has used Proof of Stake (PoS) consensus. Validators lock 32 ETH each and are randomly selected to propose blocks every 12 seconds, earning rewards for honest behaviour and being slashed for misbehaviour. As of 2026, approximately 35 million ETH is staked — roughly 30% of total supply.
EIP-1559, activated in August 2021, restructured Ethereum's fee market: every transaction pays a base fee that is permanently burned, plus an optional priority tip to validators. When network activity exceeds new issuance from staking rewards, ETH supply contracts net-deflationary. The live burn rate appears in the on-chain metrics section above.
Ethereum hosts the largest DeFi ecosystem on any chain — Uniswap, Aave, Maker, Curve, Lido — along with stablecoins like USDC and USDT, NFT marketplaces, and Layer 2 scaling networks (Arbitrum, Optimism, Base, zkSync). L2s inherit security from Ethereum mainnet while offering 10-100x lower fees and higher throughput.
Gas fees, denominated in gwei (10⁻⁹ ETH), pay validators for computation. Fees fluctuate with demand: simple transfers cost a few cents, complex DeFi interactions can range from $1-50 during peak congestion. ETH is the unit of account across the ecosystem and the predominant collateral asset in DeFi.