Ethereum is a global, open-source, decentralized blockchain platform for building and deploying smart contracts and decentralized applications. Since September 2022, it operates on a proof-of-stake consensus mechanism following "The Merge." ETH is the native cryptocurrency used for transaction fees (gas), staking, and as a medium of exchange, with an issuance model that can be deflationary depending on network activity through the EIP-1559 fee burn mechanism.