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Implementations for registrars and local resolvers for the Ethereum Name Service.

For documentation of the ENS system, see

To run unit tests, clone this repository, and run:

$ npm install
$ npm test

npm package

This repo doubles as an npm package with the compiled JSON contracts

import {
} from '@ensdomains/ens'


Implementation of the ENS Registry, the central contract used to look up resolvers and owners for domains.


Implementation of a simple first-in-first-served registrar, which issues (sub-)domains to the first account to request them.

ENS Registry interface

The ENS registry is a single central contract that provides a mapping from domain names to owners and resolvers, as described in EIP 137.

The ENS operates on 'nodes' instead of human-readable names; a human readable name is converted to a node using the namehash algorithm, which is as follows:

def namehash(name):
  if name == '':
    return '\0' * 32
    label, _, remainder = name.partition('.')
    return sha3(namehash(remainder) + sha3(label))

The registry's interface is as follows:

owner(bytes32 node) constant returns (address)

Returns the owner of the specified node.

resolver(bytes32 node) constant returns (address)

Returns the resolver for the specified node.

setOwner(bytes32 node, address owner)

Updates the owner of a node. Only the current owner may call this function.

setSubnodeOwner(bytes32 node, bytes32 label, address owner)

Updates the owner of a subnode. For instance, the owner of "" may change the owner of "" by calling setSubnodeOwner(namehash(""), sha3("bar"), newowner). Only callable by the owner of node.

setResolver(bytes32 node, address resolver)

Sets the resolver address for the specified node.


Resolvers can be found in the resolver specific repository.

Generating LLL ABI and binary data

ENS.lll.bin was generated with the following command, using the lllc packaged with Solidity 0.4.4:

$ lllc ENS.lll > ENS.lll.bin

The files in the abi directory were generated with the following command:

$ solc --abi -o abi AbstractENS.sol FIFSRegistrar.sol HashRegistrarSimplified.sol

Getting started

Install Truffle

$ npm install -g truffle

Launch the RPC client, for example TestRPC:

$ testrpc

Deploy ENS and FIFSRegistrar to the private network, the deployment process is defined at here:

$ truffle migrate --network dev.fifs

Check the truffle documentation for more information.