ENS Resolver

What is ENS Resolver?

ENS (Ethereum Name Service) Resolver is a free tool to lookup ENS domains and convert them to Ethereum wallet addresses, or reverse lookup addresses to find their associated ENS names.

ENS is like DNS for the blockchain - it converts human-readable names (like vitalik.eth) into machine-readable Ethereum addresses (like 0xd8dA...). This tool makes it easy to resolve ENS names in both directions.

What is ENS (Ethereum Name Service)?

ENS (Ethereum Name Service) is a decentralized naming system built on Ethereum that converts human-readable names into blockchain addresses.

Key features:
• Replace long addresses with easy names (vitalik.eth)
• Decentralized and censorship-resistant
• Works across all Ethereum wallets and dApps
• Can store multiple addresses (ETH, BTC, etc.)
• NFT-based ownership (ERC-721)

How it works:
• ENS names end in .eth (primary namespace)
• Each name is an NFT you own
• Names resolve to Ethereum addresses
• Reverse records show address → name
• Subdomains supported (pay.vitalik.eth)

Benefits:
• Easier to remember than 0x addresses
• One name for all your crypto addresses
• Your identity across Web3
• Transfer or sell your name
• Set avatar, social links, etc.

Examples:
• vitalik.eth → 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045
• ens.eth → 0xFe89cc7aBB2C4183683ab71653C4cdc9B02D44b7
• nickjohnson.eth → ENS founder

Popular uses:
• Wallet addresses for payments
• dApp login/identity
• NFT profiles
• DAO governance
• Web3 social accounts

How to resolve ENS name to address?

Resolving ENS name to Ethereum address (forward resolution):

Step 1: Select 'Name to Address' mode
• Enter the ENS name (e.g., vitalik.eth)
• Must include .eth extension
• Case-insensitive

Step 2: Click 'Resolve'
• Tool queries Ethereum mainnet
• Looks up ENS registry contract
• Returns the configured address

Step 3: View result
• See the Ethereum address
• Copy to clipboard
• Use for transactions

Supported formats:
• Primary names: vitalik.eth
• Subdomains: pay.vitalik.eth
• Other TLDs: name.xyz (if registered)

What gets resolved:
• ETH address (default)
• BTC address (if set)
• Other crypto addresses
• IPFS content hash
• Avatar, website, email

Common use cases:
• Send crypto to ENS name
• Verify identity
• Look up wallet balance
• Check NFT holdings
• Find social profiles

Important notes:
• Names must be registered
• Address must be set by owner
• Some names may not resolve
• Check on multiple sources
• Beware of similar names (typosquatting)

Example resolution:
Input: vitalik.eth
Output: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045

Verification:
• Cross-check on Etherscan
• Use official ENS app
• Confirm with sender
• Test with small amount first

How to lookup ENS name from address?

Reverse lookup - finding ENS name from Ethereum address:

Step 1: Select 'Address to Name' mode
• Enter Ethereum address (0x...)
• Must be valid 42-character address
• Include 0x prefix

Step 2: Click 'Resolve'
• Tool performs reverse resolution
• Queries ENS reverse records
• Returns primary ENS name if set

Step 3: View result
• See the ENS name (if exists)
• May return "Not found" if no reverse record
• Copy result

Reverse record requirements:
• Address owner must set reverse record
• Only shows primary ENS name
• Not automatic (must be configured)
• Free to set for name owners

How to set reverse record:
1. Own an ENS name
2. Go to app.ens.domains
3. Connect wallet
4. Set as Primary Name
5. Confirm transaction

Why reverse lookup?
• Identity verification
• Display names in dApps
• Wallet address labels
• Social proof
• Professional presence

Limitations:
• Not all addresses have ENS names
• Only shows primary name
• May be outdated if recently changed
• Doesn't show all owned names

Example:
Input: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045
Output: vitalik.eth

Common scenarios:
• Who sent me this transaction?
• Verify contract deployer
• Check DAO member identity
• Display user names in app
• ENS-based access control

What can ENS names resolve to?

ENS names can resolve to multiple types of data:

1. Cryptocurrency Addresses:
• ETH (Ethereum) - primary
• BTC (Bitcoin)
• LTC (Litecoin)
• DOGE (Dogecoin)
• 100+ other coins
• Multiple addresses per name

2. Content:
• IPFS hash - decentralized websites
• Swarm hash
• Arweave
• Onion (Tor)
• Redirect URLs

3. Profile Information:
• Avatar (NFT or image URL)
• Description/bio
• Website URL
• Email address
• Social media:
- Twitter handle
- GitHub username
- Discord
- Telegram
- Reddit

4. Technical Records:
• Public key
• ABI (for contracts)
• Text records (custom data)
• Multiple resolver addresses

5. Subdomains:
• Unlimited subdomains
• Different addresses per subdomain
• Examples:
- pay.vitalik.eth (payments)
- donations.vitalik.eth (donations)
- nft.vitalik.eth (NFT collection)

Setting records:
• Use app.ens.domains
• Connect wallet (must be name owner)
• Click "Add/Edit Record"
• Set each record type
• Save with transaction

Costs:
• Setting records costs gas
• No annual fee for updates
• Batch updates save gas
• Use during low gas times

Security:
• Only owner can change records
• Records stored on-chain
• Immutable history
• Verify on block explorer

Practical uses:
• One name for all crypto
• Professional Web3 profile
• Decentralized website hosting
• NFT artist portfolio
• DAO member directory
• Customer support contact

Example full profile:
vitalik.eth →
• ETH: 0xd8dA...
• BTC: bc1q...
• Avatar: ipfs://...
• Twitter: @VitalikButerin
• Website: vitalik.ca
• Email: (set privately)

ENS security and best practices?

Security considerations when using ENS:

Verification:
• Always verify ENS names on multiple sources
• Check official ENS app (app.ens.domains)
• Cross-reference with Etherscan
• Confirm with intended recipient
• Beware of typosquatting (vita1ik.eth vs vitalik.eth)

Common scams:
• Similar names with substituted characters
• Unicode lookalikes (homograph attacks)
• Fake celebrity names
• Phishing via ENS names
• Compromised name ownership

Best practices:

1. Before sending funds:
• Verify full address after resolution
• Test with small amount first
• Check transaction history
• Confirm name ownership
• Use official resolvers

2. Name ownership:
• Use hardware wallet for valuable names
• Enable 2FA on ENS manager
• Set strong passwords
• Regular security audits
• Backup recovery phrases

3. Setting records:
• Only set records you need
• Don't expose sensitive info
• Use subdomains for different purposes
• Update regularly
• Monitor for unauthorized changes

4. Reverse records:
• Set primary name intentionally
• Consider privacy implications
• Update after name transfers
• Remove if selling name

5. Subdomains:
• Control who can create subdomains
• Monitor subdomain creation
• Revoke access if needed
• Set appropriate permissions

Red flags:
• Name differs from expected
• Recently registered name
• No transaction history
• Suspicious social profiles
• Name available for cheap (should be taken)

Protection measures:
• Lock important names
• Set transfer delay
• Use multisig for valuable names
• Enable notifications
• Regular ownership checks

Recovery:
• Keep name expiry dates
• Set grace period alerts
• Maintain renewal funds
• Document all names owned
• Plan for emergencies

Privacy:
• ENS is public
• All records visible on-chain
• History is permanent
• Consider pseudonymous names
• Separate personal/business

Legal considerations:
• Name ownership disputes
• Trademark issues
• Jurisdiction unclear
• Self-custody responsibility
• No customer support

Emergency checklist:
□ Hardware wallet for names
□ Backup recovery phrases
□ Monitor name expiry
□ Set renewal reminders
□ Document all names
□ Test resolution regularly
□ Keep resolver updated
□ Review permissions
□ Check for unauthorized changes
□ Plan succession/transfer

How does ENS forward resolution actually work under the hood?

ENS uses two on-chain contracts: the Registry (maps namehash to owner+resolver) and per-name Resolvers. For vitalik.eth: compute namehash via recursive Keccak-256, query the Registry to find the resolver contract, then call resolver.addr(namehash) which returns the configured Ethereum address. All deterministic, all on Ethereum mainnet.

Why does reverse resolution sometimes return empty for an address?

Reverse records must be set explicitly by the address owner — they are NOT automatic when you register an ENS name. To set: visit app.ens.domains, connect wallet, set the name as Primary Name, confirm transaction (costs ~30k gas). Without this opt-in, reverse lookup returns null even if the wallet owns ten ENS names.

Can ENS names resolve to non-Ethereum addresses like BTC or Solana?

Yes, via SLIP-44 coin types. ENS resolvers support 600+ chains: addr.coinType(0) returns BTC, coinType(501) returns Solana, coinType(195) returns Tron, coinType(60) is ETH default. Set per-chain addresses in the ENS app. Most wallets (MetaMask, Trust, Phantom) auto-resolve their native chain via ENS lookup.

What happens if an ENS name expires while I am sending funds to it?

ENS names auto-grace for 90 days after expiry — the existing records still resolve normally. After grace, anyone can re-register and the previous owner loses control. Always verify the on-chain resolution result freshly before high-value transfers. Real-world horror story: Coinbase Custody once sent $10M to an expired-then-recaptured ENS in 2023.

Is this ENS resolver private and read-only?

Yes. This tool is 100% client-side and read-only — it never asks you to connect a wallet, never requests private keys or seed phrases, and never signs or sends transactions. All resolution happens in your browser via ethers.js.

The only network traffic is read-only JSON-RPC eth_call queries to public Ethereum mainnet endpoints (it auto-discovers from the DefiLlama chainlist and falls back to public providers such as ethereum-rpc.publicnode.com, 1rpc.io/eth, cloudflare-eth.com, eth.llamarpc.com and rpc.ankr.com/eth). These RPCs see the ENS name or address you look up, but no wallet is connected and no funds can move. Nothing you type is sent to wu.navy / wutools.com servers.

Which standards (EIP/ENSIP) power this resolver?

Forward resolution follows EIP-137: the name is normalized per ENSIP-1 (UTS-46 via ensNormalize), hashed to a namehash with recursive Keccak-256, looked up in the ENS Registry to find the Resolver, then resolver.addr() returns the address.

Reverse resolution follows EIP-181: the address is reversed at <addr>.addr.reverse and its name() record read, then forward-verified.

Addresses are validated and displayed with the EIP-55 mixed-case checksum (a single wrong-case character is rejected). Multi-chain addresses use ENSIP-9 / SLIP-44 coinType (ETH=60, BTC=0, LTC=2, DOGE=3, SOL=501). L2 and offchain names (CCIP-Read / ENSIP-10 wildcard resolution, e.g. uni.eth or cb.id Coinbase subnames) are resolved transparently by ethers when the resolver supports them.

Common Use Cases

• Send crypto to ENS names instead of long addresses
• Verify identity of transaction senders
• Display user names in dApps and wallets
• Create professional Web3 identity
• Set up payment addresses for donations
• Host decentralized websites via IPFS
• Manage multiple cryptocurrency addresses with one name
• Build DAO member directories
• Create subdomain addresses for different purposes
• Integrate ENS into smart contracts and dApps