MetaMask

MetaMask is a software cryptocurrency wallet and gateway to blockchain applications. It enables users to store and manage Ethereum and other assets, sign transactions, and connect to decentralized applications (dApps) in web browsers. Available as a browser extension for Chromium-based browsers and Firefox, as well as a mobile app for iOS and Android, MetaMask was created by ConsenSys and released in 2016. It is maintained by ConsenSys and a community of contributors.

Functionality and architecture: MetaMask stores private keys locally on the user’s device, deriving addresses from a seed phrase. It supports Ethereum mainnet, test networks, and custom networks via RPC endpoints, and handles ERC-20 and other token standards. The wallet provides a user interface for sending transactions, managing addresses, and interacting with dApps. It also offers integrated token swaps and supports hardware wallets like Ledger and Trezor for added security. Through Web3-compatible APIs, it enables dApps to request permission to access the user’s account data and to initiate transactions.

Security and privacy: As a non-custodial wallet, users retain control of their private keys, so security depends on device protection and seed phrase backups. MetaMask issues phishing warnings and domain checks to prevent drive-by scams and warns users when connecting to new sites. The product has undergone security audits and updates; users are advised to verify URLs and practice best practices, such as using hardware wallets for large holdings.

Impact and usage: MetaMask is one of the most widely used wallets in the Ethereum ecosystem, enabling access to thousands of dApps and DeFi protocols. It has shaped wallet UX and onboarding but has faced phishing and scam attempts, as well as criticism over user experience, occasional bugs, and gas estimation issues.