Develop and Deploy a Contract on Gate Layer Testnet with Foundry

Gate Layer is fully EVM-compatible. With Foundry, you can efficiently develop, test, and deploy smart contracts. This guide walks you through initialization, deployment, verification, and interaction on the Gate Layer Testnet.

Prerequisites

• OS: Linux / macOS / Windows (WSL)
• Wallet account: a locally controlled private key
• Testnet funds: a small amount of GT on Gate Layer Testnet for gas (faucet: https://www.gate.com/web3/faucet)
• RPC (Testnet): https://gatelayer-testnet.gatenode.cc

Install Foundry

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

Initialize project

forge init hello-world
cd hello-world

# Remove template files if present
rm -f src/Counter.sol script/Counter.s.sol test/Counter.t.sol

Write the contract

Create src/HelloWorld.sol:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract HelloWorld {
    string public message;

    constructor(string memory _message) {
        message = _message;
    }

    function setMessage(string memory _newMessage) public {
        message = _newMessage;
    }

    function getMessage() public view returns (string memory) {
        return message;
    }
}

The contract includes a message variable with a constructor and simple read/write functions (getMessage / setMessage).

Write and run tests

Create test/HelloWorld.t.sol:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "forge-std/Test.sol";
import "../src/HelloWorld.sol";

contract HelloWorldTest is Test {
    HelloWorld hello;

    function setUp() public {
        hello = new HelloWorld("Hello Foundry!");
    }

    function testInitialMessage() public {
        assertEq(hello.getMessage(), "Hello Foundry!");
    }

    function testSetMessage() public {
        hello.setMessage("GM Ethereum");
        assertEq(hello.getMessage(), "GM Ethereum");
    }
}

Run tests:

forge test -vvv

Deployment script

Create script/DeployHelloWorld.s.sol:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "forge-std/Script.sol";
import "../src/HelloWorld.sol";

contract DeployHelloWorld is Script {
    function run() external {
        // Use env var for private key to avoid hardcoding
        uint256 deployerPrivateKey = vm.envUint("PRIVATE_KEY");

        vm.startBroadcast(deployerPrivateKey);
        HelloWorld hello = new HelloWorld("Hello Gate Layer!");
        vm.stopBroadcast();
    }
}

Deploy to Gate Layer Testnet

export PRIVATE_KEY=0xYOUR_PRIVATE_KEY

forge script script/DeployHelloWorld.s.sol \
  --rpc-url https://gatelayer-testnet.gatenode.cc \
  --broadcast

This will deploy your contract to Gate Layer Testnet.

Verify and interact

Read contract state:

cast call <DEPLOYED_CONTRACT_ADDRESS> "getMessage()(string)" \
  --rpc-url https://gatelayer-testnet.gatenode.cc

Expected output:

"Hello Gate Layer!"

Update state (sends a transaction, requires private key):

cast send <CONTRACT_ADDRESS> "setMessage(string)" "GM Ethereum" \
  --rpc-url https://gatelayer-testnet.gatenode.cc \
  --private-key $PRIVATE_KEY

Read again:

cast call <CONTRACT_ADDRESS> "getMessage()(string)" \
  --rpc-url https://gatelayer-testnet.gatenode.cc

Expected output:

"GM Ethereum"

Wrap-up

You’ve developed, tested, deployed, and interacted with a contract on Gate Layer Testnet using Foundry. Continue expanding with more scripts and tests, or integrate a frontend to build a full DApp.

Last updated on 2025/11/18