Build and Deploy a Simple Staking Contract

This guide walks you through the process of building and deploying a basic token staking contract on Jovay, a fully Ethereum-compatible blockchain. If you're already familiar with using Foundry to develop smart contracts, you'll feel right at home — Just write, build, and deploy like you always do. New to Foundry? No problem. This document follows standard Foundry practices and includes all the steps you need to get started with confidence.

By the end, you’ll have:

• Deploy an ERC-20 token
• Build a staking contract that rewards users over time
• Stake, claim rewards, and withdraw tokens programmatically

🧰 Prerequisites

Before starting, make sure you have:

• Have Foundry Installed – Foundry
• Have an account with funds – You can get DEV tokens for testing on Jovay once every 24 hours from the Faucet
• Access to Jovay Devnet or Testnet – To deploy and interact with your token, you will need to have your own endpoint and API key, which you can get from one of the supported QuickStart

Step 1: Set Up Your Project

1. Clone the example repository:

   wget 'https://web3-static-prod.oss-ap-southeast-1.aliyuncs.com/static/Jovay/JovayExamples.tar.gz'
   tar -xvzf JovayExamples.tar.gz
   cd JovayExamples/foundry/StakingExample/

2. Install OpenZeppelin Contracts:

   Foundry uses forge to manage dependencies. Install OpenZeppelin contracts:

   forge install OpenZeppelin/openzeppelin-contracts --no-git

Step 2: Write the Token Contract

1. Create a New Solidity File:

   touch src/MyToken.sol

2. Paste the following code into src/MyToken.sol:

   // SPDX-License-Identifier: MIT
   pragma solidity ^0.8.0;
   
   import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
   
   contract MyToken is ERC20 {
       constructor(uint256 initialSupply) ERC20("MyToken", "MTK") {
           _mint(msg.sender, initialSupply);
       }
   
       function decimals() public pure override returns (uint8) {
           return 6;
       }
   }

3. Compile the Smart Contract:

   forge build

4. Test the Smart Contract (optional but recommended):

   touch c

5. Paste the following code into test/MyToken.t.sol:

   // SPDX-License-Identifier: MIT
   pragma solidity ^0.8.0;
   
   import "forge-std/Test.sol";
   import "../src/MyToken.sol";
   
   contract MyTokenTest is Test {
       MyToken public token;
       address public owner = address(0x1);
       address public alice = address(0x2);
   
       function setUp() public {
           vm.prank(owner);
           token = new MyToken(1_000_000e6); // initial supply with 6 decimals
       }
   
       // Test name and symbol
       function testNameAndSymbol() public view {
           assertEq(token.name(), "MyToken");
           assertEq(token.symbol(), "MTK");
       }
   
       // Test initial supply
       function testInitialSupply() public view {
           assertEq(token.balanceOf(owner), 1_000_000e6);
       }
   
       // Test decimals are 6
       function testDecimals() public view {
           assertEq(token.decimals(), 6);
       }
   
       // Test token transfer
       function testTransfer() public {
           vm.startPrank(owner);
           uint256 sendAmount = 100e6; // 100 tokens
   
           uint256 ownerBalanceBefore = token.balanceOf(owner);
           uint256 aliceBalanceBefore = token.balanceOf(alice);
   
           token.transfer(alice, sendAmount);
   
           uint256 ownerBalanceAfter = token.balanceOf(owner);
           uint256 aliceBalanceAfter = token.balanceOf(alice);
   
           assertEq(ownerBalanceAfter, ownerBalanceBefore - sendAmount);
           assertEq(aliceBalanceAfter, aliceBalanceBefore + sendAmount);
           vm.stopPrank();
       }
   
       // Test transfer reverts when balance is insufficient
       function testTransferRevertsWhenInsufficientBalance() public {
           vm.expectRevert();
           token.transfer(alice, 1_000_001e6); // Attempt to send more than balance
       }
   }

6. Test it:

   forge test

Step 3: Deploy the Token Contract

1. Create a Deployment Script:

   touch script/DeployMyToken.s.sol

2. Paste the following code into script/DeployToken.s.sol:

   // SPDX-License-Identifier: MIT
   pragma solidity ^0.8.20;
   
   import "forge-std/Script.sol";
   import "../src/MyToken.sol";
   
   contract DeployMyToken is Script {
       function run() external {
           uint256 deployerPrivateKey = vm.envUint("PRIVATE_KEY");
           vm.startBroadcast(deployerPrivateKey);
   
           MyToken token = new MyToken(1_000_000e6); // Initial supply
   
           console.log("Token deployed at:", address(token));
   
           vm.stopBroadcast();
       }
   }

3. Set your wallet’s private key:

   export PRIVATE_KEY=<your private key>

4. Deploy the contract:

   forge script script/DeployMyToken.s.sol --rpc-url <JOVAY_RPC_URL> --broadcast

   If your script's execution succeeds, your terminal should resemble the output below:

   

Step 4: Write the Staking Contract

1. Create a New Solidity File:

   touch src/SimpleStaking.sol

2. Paste the following code into src/SimpleStaking.sol:

   // SPDX-License-Identifier: MIT
   pragma solidity ^0.8.0;
   
   import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
   
   contract SimpleStaking {
       using SafeERC20 for IERC20;
   
       IERC20 public stakingToken;
       uint public rewardRate = 1e18;
       uint public totalStaked;
   
       struct User {
           uint amount;          // current stake amount
           uint lastTime;        // last update time
           uint unclaimedRewards; // unclaimed rewards
       }
   
       mapping(address => User) public users;
   
       constructor(address _stakingToken) {
           require(_stakingToken != address(0), "Cannot be zero address");
           stakingToken = IERC20(_stakingToken);
       }
   
       // stake
       function stake(uint amount) external {
           require(amount > 0, "Cannot stake 0");
           stakingToken.safeTransferFrom(msg.sender, address(this), amount);
   
           User storage u = users[msg.sender];
           if (u.amount > 0) {
               _update(msg.sender);
           } else {
               u.lastTime = block.timestamp;
           }
           u.amount += amount;
           totalStaked += amount;
       }
   
       // claim reward
       function claimRewards() external {
           _update(msg.sender);
           uint rewards = users[msg.sender].unclaimedRewards;
           require(rewards > 0, "No rewards to claim");
           users[msg.sender].unclaimedRewards = 0;
           stakingToken.safeTransfer(msg.sender, rewards);
       }
   
       // withdraw and claim reward
       function withdraw(uint amount) external {
           User storage u = users[msg.sender];
           require(u.amount >= amount, "Not enough staked");
   
           _update(msg.sender);
   
           uint rewards = u.unclaimedRewards;
           u.unclaimedRewards = 0;
           u.amount -= amount;
           totalStaked -= amount;
   
           stakingToken.safeTransfer(msg.sender, amount + rewards);
       }
   
       function checkRewards(address user) public view returns (uint) {
           User memory u = users[user];
           uint timeDiff = block.timestamp - u.lastTime;
           return u.unclaimedRewards + timeDiff * rewardRate * u.amount / 1e18;
       }
   
       // update reward
       function _update(address user) internal {
           User storage u = users[user];
           uint timeDiff = block.timestamp - u.lastTime;
           u.unclaimedRewards += timeDiff * rewardRate * u.amount / 1e18;
           u.lastTime = block.timestamp;
       }
   }

3. Compile the Smart Contract:

   forge build

4. Test the Smart Contract (optional but recommended):

   touch test/SimpleStaking.t.sol

5. Paste the following code into test/SimpleStaking.t.sol:

   // SPDX-License-Identifier: MIT
   pragma solidity ^0.8.20;
   
   import "forge-std/Test.sol";
   import "../src/MyToken.sol";
   import "../src/SimpleStaking.sol";
   
   contract SimpleStakingTest is Test {
       MyToken public token;
       SimpleStaking public staking;
       address owner = address(0x1);
       address alice = address(0x2);
   
       function setUp() public {
           vm.startPrank(owner);
   
           token = new MyToken(10_000_000e6); // deploy empty
           token.transfer(alice, 1000e6);
   
           staking = new SimpleStaking(address(token));
           token.transfer(address(staking), 1000_000e6);
   
           vm.stopPrank();
       }
   
       function testStakeAndGetRewards() public {
           uint amount = 100e6;
   
           // Mint and approve tokens for Alice
           vm.startPrank(alice);
           token.approve(address(staking), amount);
           staking.stake(amount);
   
           // Simulate time passing (1 hour)
           vm.warp(block.timestamp + 3600);
   
           // Check rewards
           uint rewards = staking.checkRewards(alice);
           assertGt(rewards, 0);
   
           // Claim rewards
           staking.claimRewards();
           assertEq(staking.checkRewards(alice), 0);
   
           vm.stopPrank();
       }
   
       function testWithdraw() public {
           uint amount = 100e6;
   
           vm.startPrank(alice);
           token.approve(address(staking), amount);
           staking.stake(amount);
   
           // Withdraw
           staking.withdraw(amount);
           assertEq(token.balanceOf(alice), 1_000e6);
   
           vm.stopPrank();
       }
   }

6. Test it:

   forge test

Step 5: Deploy the Staking Contract

1. Create a Deployment Script:

   touch script/DeploySimpleStaking.s.sol

2. Paste the following code into script/DeploySimpleStaking.s.sol:

   // SPDX-License-Identifier: MIT
   pragma solidity ^0.8.20;
   
   import "forge-std/Script.sol";
   import "../src/SimpleStaking.sol";
   
   contract DeploySimpleStaking is Script {
       function run() external {
           uint256 deployerPrivateKey = vm.envUint("PRIVATE_KEY");
           address tokenAddress = vm.envAddress("TOKEN_ADDRESS");
   
           vm.startBroadcast(deployerPrivateKey);
   
           SimpleStaking staking = new SimpleStaking(tokenAddress);
   
           console.log("Staking contract deployed at:", address(staking));
   
           vm.stopBroadcast();
       }
   }

3. Set your wallet’s private key and token address:

   export PRIVATE_KEY=<your private key>
   export TOKEN_ADDRESS=<your token address>

4. Deploy the contract:

   forge script script/DeploySimpleStaking.s.sol --rpc-url <JOVAY_RPC_URL> --broadcast

   If your script's execution succeeds, your terminal should resemble the output below:

   

Step 6: Interact with the Staking Contract

1. Create a scipt:

   touch script/InteractSimpleStaking.s.sol

2. Paste the following code into script/InteractSimpleStaking.s.sol:

   // SPDX-License-Identifier: MIT
   pragma solidity ^0.8.20;
   
   import "forge-std/Script.sol";
   import {console} from "forge-std/console.sol";
   import "../src/MyToken.sol";
   import "../src/SimpleStaking.sol";
   
   contract InteractStaking is Script {
       function run() external {
           uint256 deployerPrivateKey = vm.envUint("PRIVATE_KEY");
           address tokenAddress = vm.envAddress("TOKEN_ADDRESS");
           address stakingAddress = vm.envAddress("STAKING_ADDRESS");
   
           MyToken token = MyToken(tokenAddress);
           SimpleStaking staking = SimpleStaking(stakingAddress);
   
           vm.startBroadcast(deployerPrivateKey);
   
           // Approve and stake
           token.approve(stakingAddress, 10e6);
           staking.stake(10e6);
   
           console.log("Tokens staked.");
   
           // Add reward pool to Staking contract
           uint256 rewardPoolAmount = 100_000e6;
           token.transfer(address(staking), rewardPoolAmount);
   
           // Simulate time passing (1 hour)
           vm.warp(block.timestamp + 3600);
   
           // Claim rewards
           staking.claimRewards();
           console.log("Rewards claimed.");
   
           // Withdraw
           staking.withdraw(10e6);
           console.log("Tokens withdrawn.");
   
           vm.stopBroadcast();
       }
   }

3. Set your wallet’s private key, token address and staking address:

   export PRIVATE_KEY=<your private key>
   export TOKEN_ADDRESS=<your token address>
   export STAKING_ADDRESS=<your staking address>

4. Execute the script:

   forge script script/InteractSimpleStaking.s.sol --rpc-url <JOVAY_RPC_URL> --broadcast

   If your script's execution succeeds, your terminal should resemble the output below:

   

❓ Troubleshooting Tips

• Deployment fails? Make sure your wallet has enough testnet tokens.
• Can't stake or transfer? Confirm the token has been approved by the staking contract.
• Rewards not updating? Make sure you're calling _update() before checking balances.

✅ Conclusion

You've just built and deployed a fully functional token staking system on the Jovay blockchain using Foundry!

This includes:

• A mintable ERC-20 token
• A time-based reward staking contract
• Scripts for deployment and interaction

Now you can expand this system with features like:

• NFT-based staking
• Multiple reward tiers
• Locking periods
• Governance integration

If you hit any issues, refer back to this guide or consult the official Foundry documentation.

Happy coding! 🚀