Crypto Gloss

Ethereum Name Service

ENS (Ethereum Name Service) is a distributed, open naming protocol built on Ethereum smart contracts that translates human-readable names ending in “.eth” (like vitalik.eth or coinbase.eth) into machine-readable identifiers like Ethereum addresses, content hashes, and other on-chain data. Instead of copying a 42-character hex address to send ETH, ENS allows senders to type alice.eth — the protocol resolves this to Alice’s actual Ethereum address on-chain. ENS is governed by the ENS DAO, funded by a $ENS governance airdrop in 2021, and controls naming infrastructure for millions of registered names.

How ENS Works

Core components:

1. Registry:

A single Ethereum smart contract that maps names to resolver addresses. Every ENS name’s ownership and resolver are recorded here.

2. Resolver:

A per-name smart contract that converts a name to specific records:

  • ETH address (for sending ETH)
  • BTC address (for receiving Bitcoin)
  • Content hash (for IPFS/Swarm website)
  • Avatar (profile image)
  • Text records (social media handles, email, website URL)
  • Any arbitrary key-value data

3. Registrar:

For .eth names: ETH Registrar handles yearly registration and renewal. Users pay annual fees in ETH based on name length:

  • 3-char .eth names: $640/yr
  • 4-char .eth names: $160/yr
  • 5+ char .eth names: $5/yr

Name lookup flow:

  1. User sends ETH to alice.eth
  2. Wallet queries ENS registry: “What resolver does alice.eth use?”
  3. Wallet queries that resolver: “What ETH address does alice.eth map to?”
  4. Resolver returns Alice’s full Ethereum address
  5. Transaction sent to correct address

Key Features

Reverse resolution:

Maps an Ethereum address back to a human-readable name. When MetaMask or Etherscan displays your ENS name instead of your hex address.

Multi-coin addresses:

ENS resolvers support addresses for 100+ blockchains (BTC, SOL, LTC, etc.). Register alice.eth once; point it to addresses on many chains.

Subdomains:

ENS supports *.alice.eth:

  • pay.alice.eth → payment address
  • app.alice.eth → app IPFS hash
  • mail.alice.eth → encrypted email provider

Subdomains can be delegated to others; enables namespace hierarchies.

Decentralized websites:

ENS names + IPFS content hashes = decentralized websites.

  • vitalik.eth.limo (public gateway) resolves the IPFS content hash stored in the ENS record
  • Result: A website hosted on IPFS, accessed via a censorship-resistant, user-controlled domain
  • No registrar can de-platform the site; the owner controls the name on-chain

ENS Token and DAO

$ENS airdrop (November 2021):

  • ENS launched its governance token with a retroactive airdrop to:
    Anyone who had registered an ENS name before the airdrop
    Amount scaled by name registration date and duration
    Active addresses with ENS names received $10,000-$50,000+ depending on history
  • One of the most significant retroactive airdrops in DeFi history

ENS DAO:

  • Controls the .eth registrar fee revenue
  • Governs ENS protocol upgrades
  • DAO treasury: Hundreds of millions of USD in ENS tokens + ETH fees
  • Notable governance: Pled Ethereum Name Service constitution emphasizing decentralization

Notable holders: vitalik.eth, nick.eth (ENS co-founder Nick Johnson), coinbase.eth, many others

Adoption

Registered names:

  • 2M+ unique .eth names registered by 2024
  • Many high-value short names (3-4 char) owned by domain speculators
  • Premium markets for short names: 000.eth sold for 300 ETH (~$300k at the time)

Integrations:

  • MetaMask, Rainbow, Coinbase Wallet: Native ENS resolution for sends
  • OpenSea, Etherscan: Displays ENS names for addresses
  • Twitter/X: ENS names display as verified Twitter profile affiliations (Twitter partnership)
  • Uniswap, Aave, others: ENS display in DeFi UIs
  • Email clients: ENS email routing experiments

CCIP-Read (EIP-3668):

Cross-chain reading: ENS can resolve records stored on L2s or off-chain via signed proofs, reducing on-chain storage costs while maintaining trustless resolution.

How to Register an ENS Name

  1. Visit app.ens.domains
  2. Connect MetaMask or any Ethereum wallet
  3. Search for your desired .eth name
  4. Choose registration duration (1-year minimum)
  5. Two transactions: commit (anti-front-running) then register
  6. Set your records: point your ETH address, add social handles, set avatar
  7. (Optional) Enable reverse record: make your address display as yourname.eth in wallets

Fees: Annual registration fee (see above) + Ethereum gas for ~3 transactions ($2-20 depending on network conditions)

For large ENS portfolios or long-term names: secure with hardware wallet.

Social Media Sentiment

ENS is broadly respected as one of the best-executed and most genuinely useful Ethereum ecosystem projects. The technical implementation (immutable contracts, no admin keys for records, fully on-chain resolution) is widely praised. ENS is the standard for on-chain identity/naming that the ecosystem rallied around vs. alternatives (Unstoppable Domains, Space ID). Criticism: annual fees create ongoing rent (vs. traditional domain ownership), the .eth TLD isn’t ICANN-recognized (so ENS names don’t work in standard browsers without plugins), and the speculative name market creates high prices for desirable names. The ENS DAO governance has been mostly functional and drama-free relative to other DAOs.

Last updated: 2026-04

Related Terms

Sources

Buterin, V. (2021). Why We Need Wide Area Light Client Protocols. Ethereum Research.

Azouvi, S., Maller, M., & Meiklejohn, S. (2019). Egalitarian Society or Benevolent Dictator: The State of Cryptocurrency Governance. Financial Cryptography.

Kalodner, H., Möser, M., Lee, K., Goldfeder, S., Plattner, N., Ji, A., … & Narayanan, A. (2018). BlockSci: Design and Applications of a Blockchain Analysis Platform. arXiv.

Ali, M., Nelson, J., Shea, R., & Freedman, M. J. (2016). Blockstack: A Global Naming and Storage System Secured by Blockchains. USENIX ATC.

Bonneau, J., Clark, J., & Goldfeder, S. (2016). On Bitcoin as a Public Randomness Source. IACR Cryptology ePrint.