### Environment Configuration Once you have an account with a private key, create a `.env` file in the root of the foundry project and add the variables. Foundry automatically loads a `.env` file present in the project directory. The `.env` file should follow this format: ```bash ROOTSTOCK_RPC_URL=https://rpc.testnet.rootstock.io/{YOUR_APIKEY} PRIVATE_KEY=0x... ``` :::info[Info] * Your PRIVATE_KEY has to be formatted correctly, so it has to start with `0x`. * To obtain a Rootstock Rpc Url, visit the [RPC API DASHBOARD](https://rpc.rootstock.io/), create an account and get your testnet or mainnet rpc url. ::: At the root of the project, run: ```bash # To load the variables in the .env file source .env ```