What is ENS?

The Ethereum Name Service (ENS) is a distributed, open, and extensible naming system based on the Ethereum blockchain. ENS maps human-readable names like alice.eth to machine-readable identifiers such as Ethereum addresses, other cryptocurrency addresses, content hashes, metadata, and more. ENS also supports reverse resolution, making it possible to associate metadata such as primary names or interface descriptions with Ethereum addresses.

Name	Address
nick.eth	0xb8c2…67d5
jefflau.eth	0x866B…5eEE

Top-Level Domains (TLDs)

Top-Level Domains like .eth and .test are owned by smart contracts called registrars, which specify rules governing the allocation of their names. ENS enables seamless interoperability with the DNS (Domain Name System).

ETH Registrar

The ETH Registrar is the registrar for the .eth TLD. It allows trustless, decentralized names to be issued as NFTs on the Ethereum blockchain. Registration is done through smart contracts, and name ownership is secured onchain. Registration and renewals require gas.

💡

Lime: We do not use the ETH Registrar for our free namespace. Instead, Lime uses the DNS Registrar with the lime.dev domain—see below.

DNS + ENS

ENS has similar goals to DNS, the Internet’s Domain Name Service, and extends its capability. ENS supports importing DNS names through DNSSEC . You can bring your .com, .xyz, .dev, or other DNSSEC-compatible domains into the ENS ecosystem.

Supported TLDs include: .com, .xyz, .dev, .net, .org, .me, .link, .world, .day, .cool, and many more.

🟢

Lime uses this: The lime.dev domain is registered in ENS via the DNS Registrar . That allows Lime to issue ENS-compatible subnames (yourname.lime.dev) without onchain registration—the domain is already in ENS, and we control resolution for subnames.

Subnames

Because of ENS’s hierarchical nature, anyone who owns a domain at any level can control resolution for subnames. Users can create subdomains manually, or use a custom resolver to issue subnames programmatically (e.g. in an app, community, or DAO).

For instance, if Alice owns alice.eth, she can create pay.alice.eth and configure it as she wishes. Or she can use a custom resolver to issue subnames via API.

🟢

Lime uses this: Lime runs a custom resolver for *.lime.dev. We issue subnames (yourname.lime.dev) offchain via CCIP-Read (EIP-3668): the resolver contract returns an offchain lookup URL, the client fetches signed data, and resolution completes. Updates are signed with EIP-712 —no gas until you optionally publish onchain. See What is the Lime? and Hybrid vs Onchain.

ENS Architecture (Simplified)


root → registrar → controller → resolver → registry
                    ↓
              .ens.eth

For yourname.lime.dev: the lime.dev domain is in ENS via DNS; Lime’s resolver handles all *.lime.dev subnames and returns records via CCIP-Read.

Next Steps

What is the Lime? — How Lime builds on ENS
Quick Start Guide — Claim your free subname
Hybrid vs Onchain — Offchain vs onchain records