Web3 & Blockchain Basics for Developers

<h2>Introduction</h2>
<p>Web3 and blockchain technologies are transforming the way we build decentralized applications. This guide covers essential concepts for developers who want to start building on blockchain.</p>

<h3>1. What is Blockchain?</h3>
<p>A blockchain is a distributed ledger that records transactions across multiple nodes securely and transparently.</p>

<h3>2. Web3 Overview</h3>
<ul>
  <li>Web3 represents decentralized applications (dApps) interacting with blockchain networks.</li>
  <li>Users control their own data and digital assets via wallets.</li>
  <li>Common platforms: Ethereum, Solana, Polygon.</li>
</ul>

<h3>3. Smart Contracts</h3>
<p>Smart contracts are self-executing code stored on the blockchain:</p>
<pre><code>// Example: Solidity smart contract

pragma solidity ^0.8.0;

contract SimpleStorage { uint public data;

function setData(uint _data) public {
    data = _data;
}

function getData() public view returns (uint) {
    return data;
}

}</code></pre>

<h3>4. Wallets & Connecting to dApps</h3>
<ul>
  <li>Popular wallets: MetaMask, Coinbase Wallet</li>
  <li>Use <code>web3.js</code> or <code>ethers.js</code> to interact with blockchain</li>
</ul>

<h3>5. Creating a Simple dApp</h3>
<p>Example: Connect a wallet and read/write data to smart contract:</p>
<pre><code>// Example using ethers.js

import { ethers } from "ethers";

async function connectWallet() { if (window.ethereum) { await window.ethereum.request({ method: 'eth_requestAccounts' }); const provider = new ethers.providers.Web3Provider(window.ethereum); const signer = provider.getSigner(); console.log("Connected account:", await signer.getAddress()); } }</code></pre>

<h3>6. Deploying Smart Contracts</h3>
<ul>
  <li>Use Remix IDE or Hardhat for testing and deployment</li>
  <li>Deploy to testnets like Rinkeby, Goerli before mainnet</li>
</ul>

<h3>7. Example Projects</h3>
<ul>
  <li>Simple token creation (ERC20)</li>
  <li>Voting dApp</li>
  <li>Decentralized to-do list</li>
  <li>NFT marketplace</li>
</ul>

<h3>Conclusion</h3>
<p>By learning Web3 and blockchain basics, developers can start building decentralized apps, smart contracts, and explore the future of web technologies.</p>