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For documentation of the ENS system, see

npm package

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

import {
} from '@ensdomains/ens-contracts'

Importing from solidity

// Registry
import '@ensdomains/ens-contracts/contracts/registry/ENS.sol';
import '@ensdomains/ens-contracts/contracts/registry/ENSRegistry.sol';
import '@ensdomains/ens-contracts/contracts/registry/ENSRegistryWithFallback.sol';
import '@ensdomains/ens-contracts/contracts/registry/ReverseRegistrar.sol';
import '@ensdomains/ens-contracts/contracts/registry/TestRegistrar.sol';
// EthRegistrar
import '@ensdomains/ens-contracts/contracts/ethregistrar/BaseRegistrar.sol';
import '@ensdomains/ens-contracts/contracts/ethregistrar/BaseRegistrarImplementation.sol';
import '@ensdomains/ens-contracts/contracts/ethregistrar/BulkRenewal.sol';
import '@ensdomains/ens-contracts/contracts/ethregistrar/ETHRegistrarController.sol';
import '@ensdomains/ens-contracts/contracts/ethregistrar/LinearPremiumPriceOracle.sol';
import '@ensdomains/ens-contracts/contracts/ethregistrar/PriceOracle.sol';
import '@ensdomains/ens-contracts/contracts/ethregistrar/StablePriceOracle.sol';
// Resolvers
import '@ensdomains/ens-contracts/contracts/resolvers/PublicResolver.sol';
import '@ensdomains/ens-contracts/contracts/resolvers/Resolver.sol';

Accessing to binary file.

If your environment does not have compiler, you can access to the raw hardhat artifacts files at node_modules/@ensdomains/ens-contracts/artifacts/contracts/${modName}/${contractName}.sol/${contractName}.json



The ENS registry is the core contract that lies at the heart of ENS resolution. All ENS lookups start by querying the registry. The registry maintains a list of domains, recording the owner, resolver, and TTL for each, and allows the owner of a domain to make changes to that data. It also includes some generic registrars.


Interface of the ENS Registry.


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


The new implementation of the ENS Registry after the 2020 ENS Registry Migration.


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


Implementation of the reverse registrar responsible for managing reverse resolution via the .addr.reverse special-purpose TLD.


Implementation of the .test registrar facilitates easy testing of ENS on the Ethereum test networks. Currently deployed on Ropsten network, it provides functionality to instantly claim a domain for test purposes, which expires 28 days after it was claimed.


Implements an ENS registrar intended for the .eth TLD.

These contracts were audited by ConsenSys Diligence; the audit report is available here.


BaseRegistrar is the contract that owns the TLD in the ENS registry. This contract implements a minimal set of functionality:

  • The owner of the registrar may add and remove controllers.
  • Controllers may register new domains and extend the expiry of (renew) existing domains. They can not change the ownership or reduce the expiration time of existing domains.
  • Name owners may transfer ownership to another address.
  • Name owners may reclaim ownership in the ENS registry if they have lost it.
  • Owners of names in the interim registrar may transfer them to the new registrar, during the 1 year transition period. When they do so, their deposit is returned to them in its entirety.

This separation of concerns provides name owners strong guarantees over continued ownership of their existing names, while still permitting innovation and change in the way names are registered and renewed via the controller mechanism.


EthRegistrarController is the first implementation of a registration controller for the new registrar. This contract implements the following functionality:

  • The owner of the registrar may set a price oracle contract, which determines the cost of registrations and renewals based on the name and the desired registration or renewal duration.
  • The owner of the registrar may withdraw any collected funds to their account.
  • Users can register new names using a commit/reveal process and by paying the appropriate registration fee.
  • Users can renew a name by paying the appropriate fee. Any user may renew a domain, not just the name's owner.

The commit/reveal process is used to avoid frontrunning, and operates as follows:

  1. A user commits to a hash, the preimage of which contains the name to be registered and a secret value.
  2. After a minimum delay period and before the commitment expires, the user calls the register function with the name to register and the secret value from the commitment. If a valid commitment is found and the other preconditions are met, the name is registered.

The minimum delay and expiry for commitments exist to prevent miners or other users from effectively frontrunning registrations.


SimplePriceOracle is a trivial implementation of the pricing oracle for the EthRegistrarController that always returns a fixed price per domain per year, determined by the contract owner.


StablePriceOracle is a price oracle implementation that allows the contract owner to specify pricing based on the length of a name, and uses a fiat currency oracle to set a fixed price in fiat per name.


Resolver implements a general-purpose ENS resolver that is suitable for most standard ENS use cases. The public resolver permits updates to ENS records by the owner of the corresponding name.

PublicResolver includes the following profiles that implements different EIPs.

  • ABIResolver = EIP 205 - ABI support (ABI()).
  • AddrResolver = EIP 137 - Contract address interface. EIP 2304 - Multicoin support (addr()).
  • ContentHashResolver = EIP 1577 - Content hash support (contenthash()).
  • InterfaceResolver = EIP 165 - Interface Detection (supportsInterface()).
  • NameResolver = EIP 181 - Reverse resolution (name()).
  • PubkeyResolver = EIP 619 - SECP256k1 public keys (pubkey()).
  • TextResolver = EIP 634 - Text records (text()).
  • DNSResolver = Experimental support is available for hosting DNS domains on the Ethereum blockchain via ENS. The more detail is on the old ENS doc.

Developer guide

Prettier pre-commit hook

This repo runs a husky precommit to prettify all contract files to keep them consistent. Add new folder/files to prettier format script in package.json. If you need to add other tasks to the pre-commit script, add them to .husky/pre-commit

How to setup

git clone
cd ens-contracts

How to run tests

yarn test

How to publish

yarn pub

Release flow

  1. Create a feature branch from staging branch
  2. Make code updates
  3. Ensure you are synced up with staging
  4. Code should now be in a state where you think it can be deployed to production
  5. Create a "Release Candidate" release on GitHub. This will be of the form v1.2.3-RC0. This tagged commit is now subject to our bug bounty.
  6. Have the tagged commit audited if necessary
  7. If changes are required, make the changes and then once ready for review create another GitHub release with an incremented RC value v1.2.3-RC0 -> v.1.2.3-RC1. Repeat as necessary.
  8. Deploy to testnet. Open a pull request to merge the deploy artifacts into the feature branch. Create GitHub release of the form v1.2.3-testnet from the commit that has the new deployment artifacts.
  9. Get someone to review and approve the deployment and then merge. You now MUST merge this branch into staging branch.
  10. If any further changes are needed, you can either make them on the existing feature branch that is in sync or create a new branch, and follow steps 1 -> 9. Repeat as necessary.
  11. Make a deployment to ethereum mainnet from staging. Create a GitHub release of the form v1.2.3 from the commit that has the new deployment artifacts.
  12. Open a PR to merge into main. Have it reviewed and merged.

Cherry-picked release flow

Certain changes can be released in isolation via cherry-picking, although ideally we would always release from staging.

  1. Create a new branch from mainnet.
  2. Cherry-pick from staging into new branch.
  3. Deploy to ethereum mainnet, tag the commit that has deployment artifacts and create a release.
  4. Merge into mainnet.

Emergency release process

  1. Branch from main, make fixes, deploy to testnet (can skip), deploy to mainnet
  2. Merge changes back into main and staging immediately after deploy
  3. Create GitHub releases, if you didn't deploy to testnet in step 1, do it now


  • Deployed code should always match source code in mainnet releases. This may not be the case for staging.
  • staging branch and main branch should start in sync
  • staging is intended to be a practice main. Only code that is intended to be released to main can be merged to staging. Consequently:
    • Feature branches will be long-lived
    • Feature branches must be kept in sync with staging
    • Audits are conducted on feature branches
  • All code that is on staging and main should be deployed to testnet and mainnet respectively i.e. these branches should not have any undeployed code
  • It is preferable to not edit the same file on different feature branches.
  • Code on staging and main will always be a subset of what is deployed, as smart contracts cannot be undeployed.
  • Release candidates, staging and main branch are subject to our bug bounty
  • Releases follow semantic versioning and releases should contain a description of changes with developers being the intended audience