ENS Availability Checker

Check if an .eth name is available for registration. If taken, view the owner and expiry date.

How It Works

The Ethereum Name Service (ENS) allows you to register human-readable .eth names that map to Ethereum addresses. This tool queries the blockchain directly to determine whether a name is available for registration.

Availability Check

For each name, the tool performs the following on-chain lookups:

1. Compute Token ID — The label (part before .eth) is hashed with Keccak-256 to produce a token ID used by the Base Registrar contract.
2. Check Expiry — Calls nameExpires(tokenId) on the Base Registrar (0x57f1...eA85) to get the registration expiry timestamp.
3. Determine Status — If the expiry is zero (never registered) or more than 90 days in the past (grace period elapsed), the name is available. Otherwise it is taken.
4. Fetch Owner — For registered names, calls ownerOf(tokenId) on the Base Registrar to retrieve the registrant address.

Registration Rules

• Names must be at least 3 characters long.
• Registrations are for a fixed period (typically 1+ years) and must be renewed before expiry.
• After expiry, a 90-day grace period allows the owner to renew without losing the name.
• Once the grace period ends, the name becomes available to anyone.

Key Contracts

• ENS Registry — 0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e — central registry mapping namehashes to owners and resolvers.
• Base Registrar — 0x57f1887a8BF19b14fC0dF6Fd9B2acc9Af147eA85 — ERC-721 contract managing .eth name ownership and expiry dates.