Skip to content

Setting Up Your Environment Using Foundry#

Foundry is a fast, portable and modular testing and deployment tool for developing EVM smart contracts. Tests are written in Solidity to keep the workflow consistent with smart contract development and testing before deployments. Foundry itself is written in Rust.

This article, partially based on the Foundry documentation, shows how to set up Foundry and use it to build and deploy smart contracts on Flare.


1. Set up the Environment#

Follow the instructions for your operating system in the Foundry's Installation guide.

2. Create a Foundry Project#

Foundry can quick-start your development by providing a sample project:

forge init hello_foundry

This creates a new directory hello_foundry from the default template which should look something like this:

Foundry project structure

Foundry project structure.

3. Build the Contract#

To build the Counter.sol contract in the sample project run:

cd hello_foundry
forge build

When done, it should print Compiler run successful.

You will notice that two new directories have been created, out and cache:

Foundry project after build

Foundry project after build.

The out directory contains your contract artifact, such as the ABI, while the cache is used by forge to only recompile what is necessary.

4. Test the Contract#

In the test folder you should find a ready-made test file that verifies the contract works as expected.

To run tests with Foundry, you just need to run:

forge test

When finished, it should print something similar to Test result: ok. 2 passed; 0 failed; finished in 24.43ms.


Learn more about Advanced Testing using Foundry.

5. Deploy the Contract#

Forge can deploy only one contract at a time to a given network. To do so, you must provide the URL of the RPC node to access the network, and the private key of the account that will deploy the contract.

The URL can be stored in an environment variable named FOUNDRY_ETH_RPC_URL) so you do not need to supply it every time.


You are going to deploy the contract on the Coston 2 network. Make sure you have enough C2FLR in the account that will deploy the contract to pay the gas fees!

You can add C2FLR to any account using the Coston 2 Faucet.

The general Foundry command to deploy a contract is:

forge create --rpc-url <your_rpc_url> \
  --private-key <your_private_key> \

Since Solidity files may contain multiple contracts, the :<contract_name> parameter specifies which contract to deploy from the <contract_file> source file. Learn more about Deploying and Verifying Smart Contracts using Foundry.

To deploy the sample Counter contract to Flare's Coston 2 Network, run:

forge create --rpc-url \
  --private-key d8936f6eae35c73a14ea7c1aabb8d068e16889a7f516c8abc482ba4e1489f4cd \

Using the private key for your account.

Execution should look similar to this:

Foundry project deployment

Foundry project deployment.

You can check the status of the contract by copy and pasting the Deployed to: address into the Coston 2 Block Explorer.

Last update: 2023-06-06