Ethereum Name Service (ENS) is a decentralised, open naming system built on the Ethereum blockchain. It maps human-readable names, such as 'myname.eth', to machine-readable identifiers, such as Ethereum addresses, other cryptocurrency addresses, content hashes, and metadata.
ENS operates similarly to the Domain Name Service (DNS) used on the internet but is decentralised. It relies on two main components: the ENS registry and resolvers. The ENS registry is a smart contract on the Ethereum blockchain that maintains a list of all domains and subdomains, while resolvers are responsible for translating names into addresses and other resources.
Ethereum Name Service can be used to simplify cryptocurrency payments by replacing long wallet addresses with easy-to-remember domain names. It can also host decentralised websites, store metadata like email addresses and social media links, facilitate digital identity management, and enable reverse resolutions where Ethereum addresses can be mapped back to human-readable names.
ENS was conceptualised in April 2016 by Nick Johnson and launched on the Ethereum mainnet on May 4, 2017. Since then, ENS has seen several significant developments, including the expansion of character limits for domain names, governance transitions to the ENS DAO, and proposals for expanding to Layer 2 networks.