Learn through interactive tutorials that combine video lessons, code examples, and hands-on practice. Suitable for beginners and advanced developers alike.
Solidity is a high-level language for writing smart contracts on Ethereum and compatible blockchains. It's statically-typed, supports inheritance, and has a syntax similar to JavaScript. This tutorial will walk you through the fundamental concepts.
Solidity supports various data types including boolean, integers, addresses, and struct types. Understanding these is crucial for managing state variables in your contracts.
pragma solidity ^0.8.20;
contract SimpleStorage {
uint storedData;
function set(uint x) public {
storedData = x;
}
function get() public view returns (uint) {
return storedData;
}
}Functions in Solidity can be public, private, or payable. Events allow you to log important contract actions which can be efficiently read using web3.js or ethers.js.
pragma solidity ^0.8.20;
contract EventExample {
event ValueChanged(address sender, uint newValue);
uint public value;
function setValue(uint _value) public {
value = _value;
emit ValueChanged(msg.sender, _value);
}
}Understanding transactions and gas costs is essential for building efficient smart contracts. Learn how gas limits affect execution and how to optimize your contract for lower costs.
Try writing a contract that stores a user's high score. Add a function to retrieve the score and another to update it.
pragma solidity ^0.8.20;
contract HighScore {
uint public highScore;
// Your function implementations here
}Output will appear here when you click Run Code above
In this section, you'll learn how to build and optimize DeFi contracts for decentralized lending, yield farming, and liquidity provision.
Understand ERC-20, ERC-721, and how to implement stablecoin mechanisms.
Learn about up-to-date security patterns for DeFi contracts in 2025.
pragma solidity ^0.8.20;
interface IERC20 {
function totalSupply() external view returns (uint256);
function balanceOf(address account) external view returns (uint256);
// ... additional functions
}
contract LiquidityPool {
IERC20 public token;
uint public totalShares;
mapping(address => uint) public shares;
constructor(address _token) {
token = IERC20(_token);
}
function deposit(uint _amount) public {
require(_amount > 0, "Deposit amount must be positive");
uint depositedBalanceBefore = token.balanceOf(address(this));
token.transferFrom(msg.sender, address(this), _amount);
uint depositedBalanceAfter = token.balanceOf(address(this));
uint newTokens = depositedBalanceAfter - depositedBalanceBefore;
uint sharesToMint = calculateShares(newTokens);
shares[msg.sender] += sharesToMint;
totalShares += sharesToMint;
}
function calculateShares(uint _tokens) internal view returns (uint) {
if (totalShares == 0 || token.balanceOf(address(this)) == 0) {
return _tokens;
}
return (_tokens * totalShares) / token.balanceOf(address(this));
}
// Additional functions for withdrawal, fees, and governance
}This simplified example shows how a liquidity pool contract might accept deposits and issue shares. In real-world implementations you would need to add withdrawal functionality, fee handling, and governance mechanisms.