# Chainlink Smart Contracts
> [!IMPORTANT]
> Since `v1.5.0` of the Chainlink contracts package, some dependencies are no longer vendored and require the use of remappings.
> See the setup instructions for use in Solidity projects.
>
> Since `v1.4.0` of the Chainlink contracts, the contracts have been moved to their own repository:
> [chainlink-evm](https://github.com/smartcontractkit/chainlink-evm).
> Prior to that, the contracts were part of the [main Chainlink repository](https://github.com/smartcontractkit/chainlink)
## Table of Contents
- [NPM Quick Install](#npm-quick-install)
- [Setup & Installation](#setup--installation)
- [Foundry & Forge](#foundry)
- [Hardhat 2](#hardhat-2)
- [Hardhat 3](#hardhat-3)
- [Remix](#remix)
- [Package Directory Structure](#package-directory-structure)
- [Usage](#usage)
- [Local Development](#local-development)
- [Contributing](#contributing)
- [Changesets](#changesets)
## NPM Quick Install
> [!NOTE]
> For use in Solidity project(s), see the setup instructions below.
```sh
# pnpm
$ pnpm add @chainlink/contracts
```
```sh
# npm
$ npm install @chainlink/contracts --save
```
## Setup & Installation
This package relies on Solidity [remappings](https://docs.soliditylang.org/en/latest/path-resolution.html#import-remapping) to resolve import paths within your Solidity project(s). Each tool may handle [remappings](https://docs.soliditylang.org/en/latest/path-resolution.html#import-remapping) in a different manner.
In the sections below, you will find detailed instructions on this process for supported tools.
Foundry & Forge
### Step 1: Install the package
For use in your Foundry project, it is recommended to utilize `npm` or `pnpm` as your package manager for the use of this package instead of `forge install`.
```sh
# pnpm
$ pnpm add @chainlink/contracts
```
```sh
# npm
$ npm install @chainlink/contracts --save
```
If you wish to utilize `forge install`, please see the [Foundry starter kit](https://github.com/smartcontractkit/foundry-starter-kit) for detailed information.
### Step 2: Set up remappings
Set up your project's remappings. See the [Foundry documentation](https://getfoundry.sh/guides/project-setup/dependencies#remapping-dependencies) for more information.
[Foundry](https://getfoundry.sh/guides/project-setup/project-layout#project-layout) consumes a `remappings.txt` file from the project root. Create or update your project's `remappings.txt` with the following, to ensure that it loads the correct version of the dependencies you just installed into your `node_modules`:
```
@chainlink/=node_modules/@chainlink
@openzeppelin/contracts@4.7.3=node_modules/@openzeppelin/contracts-4.7.3
@openzeppelin/contracts@4.8.3=node_modules/@openzeppelin/contracts-4.8.3
@openzeppelin/contracts@4.9.6=node_modules/@openzeppelin/contracts-4.9.6
@openzeppelin/contracts@5.0.2=node_modules/@openzeppelin/contracts-5.0.2
@openzeppelin/contracts@5.1.0=node_modules/@openzeppelin/contracts-5.1.0
@openzeppelin/contracts-upgradeable/=node_modules/@openzeppelin/contracts-upgradeable/
@arbitrum/=node_modules/@arbitrum/
@eth-optimism/=node_modules/@eth-optimism/
@scroll-tech/=node_modules/@scroll-tech/
@zksync/=node_modules/@zksync/
```
Run `forge compile` to test that everything compiles correctly.
#### Troubleshooting unresolved imports
If your compilation reports unresolved imports from dependencies, add the corresponding additional remappings to `remappings.txt` (the format is `=/`).
See the [Foundry starter kit](https://github.com/smartcontractkit/foundry-starter-kit) for working examples.
Hardhat 2
### Step 1: Install the package
```sh
# pnpm
$ pnpm add @chainlink/contracts
```
```sh
# npm
$ npm install @chainlink/contracts --save
```
### Step 2: Set up remappings
Hardhat 2 does not handle remappings natively as seen in Foundry/Hardhat 3. To remap import paths, you may use a preprocessor that handles this at compile time. Refer to the remapping section of the [Hardhat 2 starter kit](https://github.com/smartcontractkit/hardhat-starter-kit/?tab=readme-ov-file#remapping) for more information.
See the [Hardhat 2 starter kit](https://github.com/smartcontractkit/hardhat-starter-kit/) for working examples.
Hardhat 3
### Step 1: Install the package
```sh
# pnpm
$ pnpm add @chainlink/contracts
```
```sh
# npm
$ npm install @chainlink/contracts --save
```
Hardhat 3 supports `remappings.txt` files in your project, as well as in Git submodules and npm dependencies. Each `remappings.txt` file applies to the directory where it's located and all its subdirectories, similar to how `.gitignore` works.
Similar to Foundry, Hardhat 3 will utilize the `remappings.txt` file located within the root directory of this Chainlink contracts package.
See the [Hardhat 3 starter kit](https://github.com/smartcontractkit/hardhat-starter-kit/tree/hardhat-3) for working examples.
Remix
Remix works out of the box and requires no additional setup or installation. The imported dependencies will be automatically installed.
## Package Directory Structure
> [!IMPORTANT]
> Since v1.5.0 of the Chainlink contracts, ABI files have been reorganized into subdirectories.
> Additionally, ABI files now follow a slightly updated naming scheme.
```sh
@chainlink/contracts
├── src # Solidity contracts
│ └── v0.8
└── abi # ABI JSON output
└── v0.8
```
#### Usage
The Solidity files themselves can be imported via the `src` directory of @chainlink/contracts:
```solidity
import {IVerifier} from '@chainlink/contracts/src/v0.8/llo-feeds/v0.5.0/interfaces/IVerifier.sol';
```
The ABI files themselves can be imported via the `abi` directory of `@chainlink/contracts`:
```
@chainlink/contracts/abi/v0.8/VRF/VRFCoordinatorV2_5.abi.json
```
## Local Development
**Note:** Contracts in `dev/` directories or with a typeAndVersion ending in `-dev` are under active development and are likely unaudited. Please refrain from using these in production applications.
```bash
# Clone Chainlink repository
$ git clone https://github.com/smartcontractkit/chainlink.git
$ cd contracts/
$ pnpm
```
Each Chainlink project has its own directory under `src/` which can be targeted using Foundry profiles. To test a specific project, run:
```bash
# Replace with the product you want to test
export FOUNDRY_PROFILE=
forge test
```
To test the llo-feeds (data streams) project:
```bash
export FOUNDRY_PROFILE=llo-feeds
forge test
```
## Contributing
Please adhere to the [Solidity Style Guide](https://github.com/smartcontractkit/chainlink-evm/blob/develop/contracts/STYLE_GUIDE.md).
Contributions are welcome! Please refer to
[Chainlink's contributing guidelines](https://github.com/smartcontractkit/chainlink/blob/develop/docs/CONTRIBUTING.md) for detailed
contribution information.
Thank you!
### Changesets
We use [changesets](https://github.com/changesets/changesets) to manage versioning the contracts.
Every PR that modifies any configuration or code should most likely be accompanied by a changeset file.
To install `changesets`:
1. Install `pnpm` if it is not already installed - [docs](https://pnpm.io/installation).
2. Run `pnpm install`.
Either after or before you create a commit, run the `pnpm changeset` command in the `contracts` directory to create an accompanying changeset entry which will reflect on the CHANGELOG for the next release.
The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).