Build with ANS

Connect to Arc

Install viem and create a public client with the settings below. On Arc mainnet, send transaction value and pay gas in native USDC. Convert amounts using 18 decimals.

pnpm add viem

import { createPublicClient, defineChain, http } from 'viem'

export const arc = defineChain({
  id: 5042,
  name: 'Arc mainnet',
  nativeCurrency: { name: 'USD Coin', symbol: 'USDC', decimals: 18 },
  rpcUrls: { default: { http: ['https://ans.family/rpc/arc'] } },
  blockExplorers: {
    default: { name: 'Arc Explorer', url: 'https://arc.exploreme.pro' }
  }
})

export const client = createPublicClient({
  chain: arc,
  transport: http()
})

Chain ID

5042

Native currency

USDC, 18 decimals

RPC

https://ans.family/rpc/arc

Address lookup

For input such as alice.arc, lowercase it and strip the suffix before validating the label. Put the suffix back when computing the namehash. Ask the controller for its resolver address rather than assuming that address will stay fixed.

import { namehash, parseAbi, zeroAddress } from 'viem'
import { client } from './arc'

const controller = '0x3Afe007AD24Ce90F17F24C8dC1E712E6bd6000AC'
const controllerAbi = parseAbi([
  'function resolver() view returns (address)'
])
const resolverAbi = parseAbi([
  'function addr(bytes32 node) view returns (address)'
])

const resolver = await client.readContract({
  address: controller,
  abi: controllerAbi,
  functionName: 'resolver'
})

const address = await client.readContract({
  address: resolver,
  abi: resolverAbi,
  functionName: 'addr',
  args: [namehash('alice.arc')]
})

if (address === zeroAddress) throw new Error('Name does not resolve')

Treat a zero-address response as a failed lookup: the registration may have expired or lack an address record. Block the send action in that case. Query ANS explicitly; an Ethereum ENS lookup will not find these records.

Registration flow

A purchase has two onchain steps. First publish a commitment that conceals the requested name, then reveal it and pay. This prevents observers from taking the name by copying a pending registration.

1. Commit the request

   Create a random 32-byte secret and retain it locally for the reveal. Pass the label, owner, duration, and secret to makeCommitment(name, owner, duration, secret). Send the resulting hash to commit(bytes32).

2. Observe the reveal window

   Reveal no earlier than 60 seconds after the commitment. The window closes after 24 hours; after that, begin again with a fresh secret.

3. Reveal and pay

   Submit register using the original commitment inputs. Attach the amount returned by rentPrice as transaction value. Confirmation mints the registration NFT to the owner and sets that wallet as the name’s destination.

import { parseAbi } from 'viem'
import { client } from './arc'

const controller = '0x3Afe007AD24Ce90F17F24C8dC1E712E6bd6000AC'
const abi = parseAbi([
  'function available(string name) view returns (bool)',
  'function rentPrice(string name, uint256 duration) view returns (uint256)'
])
const oneYear = 365n * 24n * 60n * 60n

const [available, price] = await Promise.all([
  client.readContract({
    address: controller, abi, functionName: 'available', args: ['alice']
  }),
  client.readContract({
    address: controller, abi, functionName: 'rentPrice', args: ['alice', oneYear]
  })
])

Change a destination

Address edits are authorized by the owner of the ERC-721 registration. Write the new destination to the resolver. After an NFT transfer, use reclaim when the registry ownership also needs to be updated.

import { namehash, parseAbi } from 'viem'

const resolverAbi = parseAbi([
  'function setArcAddress(bytes32 node, address target)'
])

await walletClient.writeContract({
  address: '0xCFaaBe54713131E988Eb76948aa6184210EB29dF',
  abi: resolverAbi,
  functionName: 'setArcAddress',
  args: [namehash('alice.arc'), newAddress],
  account
})

Contract addresses

Begin with the controller address below. It reports the current registry, registrar, and resolver. These protocol contracts use transparent upgradeable proxies.

Rules and limitations

Accepted names

Labels must be 3 to 63 characters long and use lowercase ASCII letters, digits, or internal hyphens. Leading and trailing hyphens are rejected.

After expiry

Resolution returns zero as soon as registration expires. A renewal grace period follows before another wallet can register the label.

Admin controls

The configured ProxyAdmin can upgrade the controller, registry, registrar, and resolver. Fetch their active addresses through the controller when it offers a getter.

Review status

No independent contract audit has been published. Automated tests are available, but do not replace your own review.