ens.html

---
layout: nodes.liquid
section: ethereum
date: Last Modified
title: "Using ENS with Data Feeds"
permalink: "docs/data-feeds/ens/"
excerpt: "Ethereum Name Service"
metadata:
description: "How Chainlink uses the Ethereum Name Service for Data Feed contract addresses."
image:
0: "/files/7c891b4-link.png"
---

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<script src="/ens.js"></script>

Chainlink is moving to the <a href="https://docs.ens.domains/" target="_blank">Ethereum Name Service (ENS)</a> as the source of truth for Data Feed addresses. ENS is a distributed, open, and extensible naming system based on the Ethereum blockchain, which eliminates the need to copy or type long addresses. Instead, addresses can be obtained in deployed contracts or, alternatively, using off-chain scripts that read the state of the blockchain.

<div>
  <div>
    <h3>Lookup</h3>
    <div class="col-xs-12 col-md-4">
      <b>Pair:</b><br>
      <select class="cl-select" onchange="getDropdownAddress()" name="pairs" id="pairs">
        <option value="">Choose Pair</option>
        <option value="aave-eth.data.eth">AAVE / ETH</option>
        <option value="aave-usd.data.eth">AAVE / USD</option>
        <option value="ada-usd.data.eth">ADA / USD</option>
        <option value="adx-usd.data.eth">ADX / USD</option>
        <option value="ant-eth.data.eth">ANT / ETH</option>
        <option value="aud-usd.data.eth">AUD / USD</option>
        <option value="bal-eth.data.eth">BAL / ETH</option>
        <option value="bat-eth.data.eth">BAT / ETH</option>
        <option value="bch-usd.data.eth">BCH / USD</option>
        <option value="bnb-usd.data.eth">BNB / USD</option>
        <option value="bnt-eth-bancor.data.eth">BNT / ETH (Bancor)</option>
        <option value="bnt-eth.data.eth">BNT / ETH</option>
        <option value="bnt-usd.data.eth">BNT / USD</option>
        <option value="brent-usd.data.eth">BRENT / USD</option>
        <option value="btc-ars.data.eth">BTC / ARS</option>
        <option value="btc-difficulty.data.eth">BTC Difficulty</option>
        <option value="btc-eth.data.eth">BTC / ETH</option>
        <option value="btc-usd.data.eth">BTC / USD</option>
        <option value="busd-eth.data.eth">BUSD / ETH</option>
        <option value="bzrx-eth.data.eth">BZRX / ETH</option>
        <option value="chf-usd.data.eth">CHF / USD</option>
        <option value="comp-eth.data.eth">COMP / ETH</option>
        <option value="comp-usd.data.eth">COMP / USD</option>
        <option value="cro-eth.data.eth">CRO / ETH</option>
        <option value="crv-eth.data.eth">CRV / ETH</option>
        <option value="dai-eth.data.eth">DAI / ETH</option>
        <option value="dai-usd.data.eth">DAI / USD</option>
        <option value="dash-usd.data.eth">DASH / USD</option>
        <option value="dmg-eth.data.eth">DMG / ETH</option>
        <option value="dot-usd.data.eth">DOT / USD</option>
        <option value="enj-eth.data.eth">ENJ / ETH</option>
        <option value="eos-usd.data.eth">EOS / USD</option>
        <option value="etc-usd.data.eth">ETC / USD</option>
        <option value="eth-usd.data.eth">ETH / USD</option>
        <option value="eth-xdr.data.eth">ETH / XDR</option>
        <option value="eur-mwh.data.eth">EUR / MWh</option>
        <option value="eur-usd.data.eth">EUR / USD</option>
        <option value="fast-gas-gwei.data.eth">Fast Gas / Gwei</option>
        <option value="fil-usd.data.eth">FIL / USD</option>
        <option value="fnx-usd.data.eth">FNX / USD</option>
        <option value="ftm-eth.data.eth">FTM / ETH</option>
        <option value="ftse-gbp.data.eth">FTSE / GBP</option>
        <option value="gbp-usd.data.eth">GBP / USD</option>
        <option value="jpy-usd.data.eth">JPY / USD</option>
        <option value="knc-eth.data.eth">KNC / ETH</option>
        <option value="knc-usd.data.eth">KNC / USD</option>
        <option value="lend-eth.data.eth">LEND / ETH</option>
        <option value="lend-usd.data.eth">LEND / USD</option>
        <option value="link-eth-bancor.data.eth">LINK / ETH (Bancor)</option>
        <option value="link-eth.data.eth">LINK / ETH</option>
        <option value="link-usd.data.eth">LINK / USD</option>
        <option value="lrc-eth.data.eth">LRC / ETH</option>
        <option value="ltc-usd.data.eth">LTC / USD</option>
        <option value="mana-eth.data.eth">MANA / ETH</option>
        <option value="mkr-eth.data.eth">MKR / ETH</option>
        <option value="mln-eth.data.eth">MLN / ETH</option>
        <option value="n225-jpy.data.eth">N225 / JPY</option>
        <option value="nmr-eth.data.eth">NMR / ETH</option>
        <option value="orchid.data.eth">Orchid</option>
        <option value="oxt-usd.data.eth">OXT / USD</option>
        <option value="ren-eth-bancor.data.eth">REN / ETH (Bancor)</option>
        <option value="ren-eth.data.eth">REN / ETH</option>
        <option value="ren-usd.data.eth">REN / USD</option>
        <option value="rep-eth.data.eth">REP / ETH</option>
        <option value="rlc-eth.data.eth">RLC / ETH</option>
        <option value="scex-usd.data.eth">sCEX / USD</option>
        <option value="sdefi-usd.data.eth">sDEFI / USD</option>
        <option value="snx-eth.data.eth">SNX / ETH</option>
        <option value="snx-usd.data.eth">SNX / USD</option>
        <option value="susd-eth.data.eth">SUSD / ETH</option>
        <option value="sxp-usd.data.eth">SXP / USD</option>
        <option value="total-marketcap-usd.data.eth">Total Marketcap / USD</option>
        <option value="trx-usd.data.eth">TRX / USD</option>
        <option value="tusd-eth.data.eth">TUSD / ETH</option>
        <option value="tusd-reserves.data.eth">TUSD Reserves</option>
        <option value="tusd-supply.data.eth">TUSD Supply</option>
        <option value="uma-eth.data.eth">UMA / ETH</option>
        <option value="uni-eth.data.eth">UNI / ETH</option>
        <option value="uni-usd.data.eth">UNI / USD</option>
        <option value="usdc-eth.data.eth">USDC / ETH</option>
        <option value="usdk-usd.data.eth">USDK / USD</option>
        <option value="usdt-eth.data.eth">USDT / ETH</option>
        <option value="wnxm-eth.data.eth">WNXM / ETH</option>
        <option value="wom-eth.data.eth">WOM / ETH</option>
        <option value="wti-usd.data.eth">WTI / USD</option>
        <option value="xag-usd.data.eth">XAG / USD</option>
        <option value="xau-usd.data.eth">XAU / USD</option>
        <option value="xhv-usd.data.eth">XHV / USD</option>
        <option value="xmr-usd.data.eth">XMR / USD</option>
        <option value="xrp-usd.data.eth">XRP / USD</option>
        <option value="xtz-usd.data.eth">XTZ / USD</option>
        <option value="yfi-eth.data.eth">YFI / ETH</option>
        <option value="yfi-usd.data.eth">YFI / USD</option>
        <option value="zrx-eth.data.eth">ZRX / ETH</option>
      </select>
    </div>
    <div class="col-xs-12 col-md-4">
      <b>ENS Name:</b><br>
      <a id="address1-label-link" target="_blank">
        <pre><code id="address1-label" class="language-none">-</code></pre>
      </a>
    </div>
    <div class="col-xs-12 col-md-8">
      <b>Address:</b><br>
      <a id="address1-link" target="_blank">
        <pre><code  id="address1" class="language-none">-</code></pre>
      </a>
    </div>
    <div class="col-xs-12 col-md-8">
      <b>Hash ID:</b><br>
      <a id="address1-hash-link" target="_blank">
        <pre><code  id="address1-hash" class="language-none">-</code></pre>
      </a>
    </div>
  </div>
</div>

<hr>

<div>
	<h3>Manual Lookup<h3>
	<div class="col-xs-12 col-md-4">
    <input id="asset-1" type="text" value="ETH" size="5"></input>
  	<span>/</span>
    <input id="asset-2" type="text" value="USD" size="5"></input>
	</div>
	<div class="col-xs-12 col-md-8">
		<a id="get-price-button" href="javascript:getManualAddress();" class="cl-button--ghost cl-button--ghost-sm">Lookup</a>
	</div>
	<div class="col-xs-12 col-md-4">
    <b>ENS Name:</b><br>
    <a id="address2-label-link" target="_blank">
      <pre><code id="address2-label" class="language-none">-</code></pre>
    </a>
	</div>
  <div class="col-xs-12 col-md-8">
    <b>Address:</b><br>
    <a id="address2-link" target="_blank">
      <pre><code  id="address2" class="language-none">-</code></pre>
    </a>
	</div>
</div>

{% markdown %}
# Naming Structure

Chainlink data feeds fall under the `data.eth` naming suffix. To obtain a specific feed address, prefix this with the assets in the feed, separated by a dash (-).

|Pair|ENS Domain Name|
|:---|:---|
|ETH / USD|`eth-usd.data.eth`|
|BTC / USD|`btc-usd.data.eth`|
|...|`...`|

## Subdomains

By default, the base name structure (`eth-usd.data.eth`) returns the proxy address for that feed. However, subdomains enable callers to retrieve other associated contract addresses, as shown in the following table.

|Contract Addresses|Subdomain Prefix|Example|
|:-----------|:------------------|:---------|
|Proxy|`proxy`|`proxy.eth-usd.data.eth`|
|Underlying aggregator|`aggregator`|`aggregator.eth-usd.data.eth`|
|Proposed aggregator|`proposed`|`proposed.eth-usd.data.eth`|

# Architecture

## Resolver

For each network, there is a single Chainlink resolver, which does not change. Its address can be obtained using the `data.eth` domain. This resolver manages the subdomains associated with `data.eth`.

|Network|Resolver Address|
|:-----------|:------------------|
|Ethereum Mainnet|<a href="https://app.ens.domains/address/0x122eb74f9d0F1a5ed587F43D120C1c2BbDb9360B/" target="_blank">`0x122eb74f9d0F1a5ed587F43D120C1c2BbDb9360B`</a>|

## Listening for Address Changes

When a new aggregator is deployed for a specific feed, it is first proposed, and when accepted becomes the aggregator for that feed. During this process, the `proposed` and `aggregator` subdomains for that feed will change. With each change, the resolver emits an `AddrChanged` event, using the feed subdomain (for example: `eth-usd.data.eth`) as the indexed parameter.

**Example**: If you want to listen for when the aggregator of the ETH / USD feed changes, set up a listener to track the `AddrChanged` event on the resolver, using a filter like this: `ethers.utils.namehash('aggregator.eth-usd.data.eth')`.

# Obtaining Addresses

> 🚧 Reverse Lookup
>
> Reverse lookup is not supported.

## Javascript

The example below uses Javascript Web3 library to interact with ENS. See the <a href="https://docs.ens.domains/dapp-developer-guide/resolving-names" target="_blank">ENS documentation</a> for the full list of languages and libraries libraries that support ENS.

This example logs the address of the data feed on the Ethereum mainnet for ETH / USD prices.

```javascript
{% include 'samples/PriceFeeds/ENSConsumer.js' %}
```

## Solidity

In Solidity, the address of the ENS registry must be known. According to <a href="https://docs.ens.domains/ens-deployments" target="_blank">ENS documentation</a>, this address is the same across Mainnet and Goerli networks:

ENS registry address: <a href="https://etherscan.io/address/0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e" target="_blank">`0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e`</a>.

Also, instead of using readable string names like `eth-usd.data.eth`, resolvers accept bytes32 hash IDs for names. Hash IDs can be retrieved from <a href="https://thegraph.com/explorer/subgraph/ensdomains/ens" target="_blank">this subgraph</a> or via this npm package <a href="https://www.npmjs.com/package/@ensdomains/eth-ens-namehash" target="_blank">eth-ens-namehash</a>.

"ETH / USD" hash: `0xf599f4cd075a34b92169cf57271da65a7a936c35e3f31e854447fbb3e7eb736d`

```solidity
{% include 'samples/PriceFeeds/ENSConsumer.sol' %}
```
{% endmarkdown %}