/setup-solidity-contracts

name: setup-solidity-contracts
description: "Set up a Solidity smart contract project with OpenZeppelin Contracts. Use when users need to: (1) create a new Hardhat or Foundry project, (2) install OpenZeppelin Contracts dependencies for Solidity, (3) configure remappings for Foundry, or (4) understand Solidity import conventions for OpenZeppelin."
license: AGPL-3.0-only
metadata:
  author: OpenZeppelin

Solidity Setup

For existing projects, detect the framework by looking for `hardhat.config.*` (Hardhat) or `foundry.toml` (Foundry). For new projects, ask the user which framework they prefer.

Hardhat Setup

• Initialize project (only if starting a new project)

npx hardhat init        # Hardhat v2
npx hardhat --init      # Hardhat v3

• Install OpenZeppelin Contracts:

npm install @openzeppelin/contracts

• If using upgradeable contracts, also install the upgradeable variant:

npm install @openzeppelin/contracts-upgradeable

Foundry Setup

• Install Foundry

curl -L https://foundry.paradigm.xyz | bash
foundryup

• Initialize project (only if starting a new project)

forge init my-project
cd my-project

• Add OpenZeppelin Contracts:

forge install OpenZeppelin/openzeppelin-contracts@v<VERSION>

• If using upgradeable contracts, also add the upgradeable variant:

forge install OpenZeppelin/openzeppelin-contracts-upgradeable@v<VERSION>

> Look up the current version from https://github.com/OpenZeppelin/openzeppelin-contracts/releases. Pin to a release tag — without one, `forge install` pulls the default branch, which may be unstable.

• `remappings.txt` (if not using upgradeable contracts)

@openzeppelin/contracts/=lib/openzeppelin-contracts/contracts/

• `remappings.txt` (if using upgradeable contracts)

@openzeppelin/contracts/=lib/openzeppelin-contracts-upgradeable/lib/openzeppelin-contracts/contracts/
@openzeppelin/contracts-upgradeable/=lib/openzeppelin-contracts-upgradeable/contracts/

> **Note** > The above remappings mean that both `@openzeppelin/contracts/` (including proxy contracts) and `@openzeppelin/contracts-upgradeable/` come from the `openzeppelin-contracts-upgradeable` submodule and its subdirectories, which includes its own transitive copy of `openzeppelin-contracts` of the same release version number. This format is needed for Etherscan verification to work. Particularly, any copies of `openzeppelin-contracts` that are installed separately are NOT used.

Import Conventions

• Standard: `@openzeppelin/contracts/token/ERC20/ERC20.sol`
• Upgradeable: `@openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol`
• Use upgradeable variants only when deploying behind proxies; otherwise use standard contracts.