Ethereum Name Service (ENS) is an open-source, distributed, and extensible naming system built on the Ethereum blockchain. It aims to make Ethereum-based web more accessible and understandable for humans, much like how the Internet’s Domain Name Service (DNS) simplifies internet navigation. ENS transforms human-readable Ethereum addresses into machine-readable alphanumeric codes, and vice versa. This functionality allows users to replace long, complex Ethereum addresses with simple, memorable ones, enhancing user experience and facilitating wider adoption of blockchain technologies. ENS is not a company but an open-source project that seeks to become a vital piece of infrastructure for Web3, similar to how DNS is integral to the internet.

ENS operates on two primary smart contracts. The first is the ENS registry, which records domains registered on ENS and stores information about each of them, including the domain owner and the domain resolver. The second smart contract is the resolver, which translates machine-readable addresses to domain names and vice versa. This contract also matches each domain to its corresponding user, website, or address. ENS uses a system of dot-separated hierarchical names called domains, with domain owners having full control over their subdomains. This system is similar to the one used by DNS, making it familiar for most internet users.

ENS aims to simplify the user experience in the blockchain space by replacing machine-readable alphanumeric codes with short, easy-to-remember links. This functionality can be used to receive any cryptocurrency, token, or non-fungible token (NFT) to a simple link, aiming to make blockchain technology less technical and more accessible. ENS also supports 'reverse resolution', enabling the association of metadata such as canonical names or interface descriptions with Ethereum addresses. Furthermore, ENS can be used to launch censorship-resistant decentralized websites. Users can upload their website to the InterPlanetary File System (IPFS) and access it with their ENS name, enhancing the decentralization and security of web content.

ENS was initially a part of the Ethereum Foundation, but it spun off as a separate organization in 2018. Its Lead Developer is Nick Johnson, a software engineer from New Zealand who previously worked at Google and the Ethereum Foundation. ENS had a retroactive airdrop in November 2021 that rewarded users who had registered addresses before the project launched its token. ENS continues to work towards its goal of making the Ethereum-based web easier to access and comprehend for humans.