Data feeds are available on the following networks:

• EVM-compatible networks
• Solana network

You can use smart contracts to get asset prices on EVM-compatible networks. These examples show you how to get the price of Ethereum (ETH) on the Ethereum network, but you can modify the examples to work on other EVM-compatible networks as well. The list of data feeds for each network are available on the Data Feed Contracts page. For development, use testnet data feeds such as the ETH/USD Feed on the Kovan testnet.

You can write smart contracts that consume data feeds using several languages, but this guide shows you the following examples:

• Solidity
• Javascript with web3.js
• Python with Web3.py

Solidity

To consume price data, your smart contract should reference AggregatorV3Interface, which defines the external functions implemented by Data Feeds.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;

import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";

contract PriceConsumerV3 {

    AggregatorV3Interface internal priceFeed;

    /**
     * Network: Kovan
     * Aggregator: ETH/USD
     * Address: 0x9326BFA02ADD2366b30bacB125260Af641031331
     */
    constructor() {
        priceFeed = AggregatorV3Interface(0x9326BFA02ADD2366b30bacB125260Af641031331);
    }

    /**
     * Returns the latest price
     */
    function getLatestPrice() public view returns (int) {
        (
            uint80 roundID, 
            int price,
            uint startedAt,
            uint timeStamp,
            uint80 answeredInRound
        ) = priceFeed.latestRoundData();
        return price;
    }
}

The latestRoundData function returns five values representing information about the latest price data. See the Data Feeds API Reference for more details.

Javascript

This example uses web3.js to retrieve feed data from the ETH / USD feed on the Ethereum network.

const web3 = new Web3("https://kovan.infura.io/v3/<infura_project_id>");
const aggregatorV3InterfaceABI = [{"inputs":[],"name":"decimals","outputs":[{"internalType":"uint8","name":"","type":"uint8"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"description","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"uint80","name":"_roundId","type":"uint80"}],"name":"getRoundData","outputs":[{"internalType":"uint80","name":"roundId","type":"uint80"},{"internalType":"int256","name":"answer","type":"int256"},{"internalType":"uint256","name":"startedAt","type":"uint256"},{"internalType":"uint256","name":"updatedAt","type":"uint256"},{"internalType":"uint80","name":"answeredInRound","type":"uint80"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"latestRoundData","outputs":[{"internalType":"uint80","name":"roundId","type":"uint80"},{"internalType":"int256","name":"answer","type":"int256"},{"internalType":"uint256","name":"startedAt","type":"uint256"},{"internalType":"uint256","name":"updatedAt","type":"uint256"},{"internalType":"uint80","name":"answeredInRound","type":"uint80"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"version","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"}];
const addr = "0x9326BFA02ADD2366b30bacB125260Af641031331";
const priceFeed = new web3.eth.Contract(aggregatorV3InterfaceABI, addr);
priceFeed.methods.latestRoundData().call()
    .then((roundData) => {
        // Do something with roundData
        console.log("Latest Round Data", roundData)
    });

Python

This example uses Web3.py to retrieve feed data from the ETH / USD feed on the Ethereum network.

web3 = Web3(Web3.HTTPProvider('https://kovan.infura.io/v3/<infura_project_id>'))
abi = '[{"inputs":[],"name":"decimals","outputs":[{"internalType":"uint8","name":"","type":"uint8"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"description","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"uint80","name":"_roundId","type":"uint80"}],"name":"getRoundData","outputs":[{"internalType":"uint80","name":"roundId","type":"uint80"},{"internalType":"int256","name":"answer","type":"int256"},{"internalType":"uint256","name":"startedAt","type":"uint256"},{"internalType":"uint256","name":"updatedAt","type":"uint256"},{"internalType":"uint80","name":"answeredInRound","type":"uint80"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"latestRoundData","outputs":[{"internalType":"uint80","name":"roundId","type":"uint80"},{"internalType":"int256","name":"answer","type":"int256"},{"internalType":"uint256","name":"startedAt","type":"uint256"},{"internalType":"uint256","name":"updatedAt","type":"uint256"},{"internalType":"uint80","name":"answeredInRound","type":"uint80"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"version","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"}]'
addr = '0x9326BFA02ADD2366b30bacB125260Af641031331'
contract = web3.eth.contract(address=addr, abi=abi)
latestData = contract.functions.latestRoundData().call()
print(latestData)

How Do Data Feeds Get Their Data?

Data Feeds are aggregated from many data sources by a decentralized set of independent Node Operators. The Decentralized Data Model describes this in detail.

More Aggregator Functions

Getting the latest price is not the only data that aggregators can retrieve. You can also retrieve historical price data. To learn more, see the Historical Price Data page.