This page explains how to install and use the Chainlink Library in your projects.

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If you're new to smart contract development and want a step-by-step guide, try out our Beginner Walkthrough

Install into Existing Projects

Chainlink is supported by Hardhat, Brownie, Truffle and other frameworks.

If you already have a project, you can add Chainlink to it by using the following package managers.

NPM

Install using NPM

npm install @chainlink/contracts --save

Yarn

Install using Yarn

yarn add @chainlink/contracts

Create a New Project

If you're creating a new project from scratch, these commands will help you set up your project to interact with Chainlink.

Hardhat Box

Install hardhat

npm install --save-dev hardhat

Then, clone the boilerplate repository.

git clone https://github.com/smartcontractkit/chainlink-hardhat-box
cd chainlink-hardhat-box

For more information on Hardhat, see our blog post How to use Hardhat with Chainlink. Alternatively, visit the repo for more instructions.

Brownie Mix

Install Brownie with pip:

pip install eth-brownie

With Brownie installed, run the commands below to open a Brownie project into a new directory.

mkdir MyChainlinkProject
cd MyChainlinkProject/
brownie bake chainlink-mix
cd chainlink-mix

For more information on working with Bownie, see our blog how to use Brownie with Chainlink or visit the repo to learn more.

Environment variables are required when working with Brownie. Learn how to set environment variables.

Truffle Box

Install Truffle with NPM:

npm install truffle -g

Once installed, unbox the Chainlink box.

mkdir MyChainlinkProject
cd MyChainlinkProject/
truffle unbox smartcontractkit/box

For more details on how to use the Truffle, see our blog post. Alternatively, visit the repo for more information.

Using Chainlink Contracts

Once you have the Chainlink library installed, you can leverage the Chainlink ecosystem.

If you're interested in retrieving up to date crypto prices in your contracts, learn more about our Price Feeds.

If you need to consume randomness in your contracts, learn about Chainlink VRF.

And if you want your contracts to retrieve data from off-chain APIs, learn about Using Any API.

Testing Chainlink Contracts

See our blog post on Testing Chainlink Smart Contracts or watch the Chainlink Hackathon Workshop.

Tests samples can be found on Chainlink Hardhat Box and Chainlink Truffle Box respectively.