# Deploy a contract with Foundry or Hardhat

> Original page: https://docs.blockvectra.com/en/guides/deploy-contract/

## Select the network

Follow the target chain's integration guide (accessed via [Supported Chains](https://docs.blockvectra.com/en/chains/)) to create `network.mjs` and export `RPC_URL` and `CHAIN_ID`. Chain guides read the chain ID and method policy from [GET /v1/chains](https://api.blockvectra.com/v1/chains) and explain the gas token, whether a separate broadcasting RPC is required, and chain-specific deployment settings.

Choose one tool below. Both deploy the same small contract without constructor arguments.

Fund the deployer with the selected network’s native gas token. Set `DEPLOYER_PRIVATE_KEY` securely in your local environment; never commit it. The following commands broadcast a transaction and spend gas.

Create `Hello.sol` with no constructor arguments:

```solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;
contract Hello {
    event Ping(address indexed sender);
    function ping() external { emit Ping(msg.sender); }
    function hello() external pure returns (string memory) {
        return "hello";
    }
}
```

### Foundry

In an initialized Foundry project, place the contract at `src/Hello.sol` and use this `foundry.toml`:

```toml
[profile.default]
src = "src"
out = "out"
libs = ["lib"]
solc_version = "0.8.24"
evm_version = "paris"

[rpc_endpoints]
target = "${RPC_URL}"
```

```bash
: "${RPC_URL:?Set RPC_URL}" "${CHAIN_ID:?Set CHAIN_ID}" "${DEPLOYER_PRIVATE_KEY:?Set deployer key}"
test "$(cast chain-id --rpc-url "$RPC_URL")" = "$CHAIN_ID" || exit 1
forge build
forge create src/Hello.sol:Hello --rpc-url target \
  --chain "$CHAIN_ID" --private-key "$DEPLOYER_PRIVATE_KEY" --broadcast
```

Keep the transaction hash and deployed address. Use `cast receipt "$TX_HASH" --rpc-url "$RPC_URL"` to inspect inclusion and status, then `cast call "$CONTRACT_ADDRESS" "hello()(string)" --rpc-url "$RPC_URL"` to read the contract. Set these two variables from the deployment output.

### Hardhat 2 with ethers 6

In a separate CommonJS project (`npm init -y`), install `npm install --save-dev hardhat@2 @nomicfoundation/hardhat-ethers@3 ethers@6`. Place the same contract at `contracts/Hello.sol`. Save this as `hardhat.config.cjs`:

```js
require('@nomicfoundation/hardhat-ethers');
const { RPC_URL, CHAIN_ID, DEPLOYER_PRIVATE_KEY } = process.env;
if (!RPC_URL || !/^[1-9][0-9]*$/.test(CHAIN_ID ?? '') || !DEPLOYER_PRIVATE_KEY) {
  throw new Error('Set RPC_URL, CHAIN_ID and DEPLOYER_PRIVATE_KEY');
}
module.exports = {
  solidity: { version: '0.8.24', settings: { evmVersion: 'paris' } },
  networks: {
    target: { url: RPC_URL, chainId: Number(CHAIN_ID), accounts: [DEPLOYER_PRIVATE_KEY] },
  },
};
```

Create the `scripts` directory and save as `scripts/deploy.cjs`:

```js
const { ethers } = require('hardhat');
async function main() {
  const contract = await ethers.deployContract('Hello');
  console.log(contract.deploymentTransaction().hash);
  await contract.waitForDeployment();
  console.log(await contract.getAddress());
}
main().catch(error => { console.error(error); process.exitCode = 1; });
```

```bash
npx hardhat compile
npx hardhat run scripts/deploy.cjs --network target
```

The network’s `chainId` is checked against the RPC. See the [Hardhat 2 network settings](https://v2.hardhat.org/hardhat-runner/docs/config) and [Foundry settings](https://www.getfoundry.sh/config/index.html) (accessed: 2026-10-07).

## Read events

Set `LOG_ADDRESS` to the deployed address. Follow the event reading method in the target chain's guide (WebSocket subscription or HTTP chunked polling, depending on the chain's `ws` field in `/v1/chains`) to read `Ping` events after calling `ping()`.