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🔨 Compile & Deploy: From Code to Blockchain

Turn Solidity into bytecode and broadcast it to the Ethereum network

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Introduction

Writing Contract

Compilation & Deployment

Interaction & Verification

Key Takeaways

←

Writing Contract

⚙️ Compilation & Deployment

Let's compile your contract into bytecode and deploy it to the Sepolia testnet. Watch the entire process step-by-step!

🎮 Interactive: Deployment Process Simulator

Step through the deployment journey from compilation to live contract

Step 1 of 6

Write Contract

📝

Write Contract

⚙️

Compile

🌐

Select Network

🚀

Deploy Transaction

⛏️

Mining

✅

Contract Live!

📝

Write Contract

You wrote SimpleStorage.sol

Contract code ready in Remix IDE

Output:

SimpleStorage.sol (7 lines of Solidity)

🔨 What is Compilation?

Compilation translates human-readable Solidity code into machine-readable bytecode that the EVM can execute.

📝

Input: Solidity

contract SimpleStorage {

uint256 public data;

}

Human-readable code you wrote

⚙️

Output: Bytecode

0x608060405234801...

Machine code for EVM execution

📋 Compilation Outputs

Bytecode

The actual code that runs on the EVM. Hexadecimal string starting with 0x.

Example:

0x608060405234801561001057600080fd5b5060405161012c38...

ABI (Application Binary Interface)

JSON description of contract's functions. Tells Web3.js how to interact with your contract.

Example:

[{
  "inputs": [{"type": "uint256"}],
  "name": "set",
  "type": "function"
}]

Metadata

Additional info: compiler version, source code hash, optimization settings.

Compiler: solc v0.8.0

Optimization: 200 runs

EVM Version: London

🚀 How to Deploy in Remix

1️⃣

Compile Contract

Click "Solidity Compiler" tab → Click "Compile SimpleStorage.sol"

✅ Compilation successful

2️⃣

Select Environment

Click "Deploy & Run" tab → Environment: "Injected Provider - MetaMask"

🦊 MetaMask will connect

3️⃣

Choose Network

In MetaMask: Switch to "Sepolia Test Network"

🌐 Network: Sepolia

4️⃣

Deploy

Select "SimpleStorage" → Click orange "Deploy" button

🚀 MetaMask popup: Confirm transaction

5️⃣

Wait for Confirmation

Transaction appears in Remix console. Wait ~15 seconds for block confirmation.

✅ Contract deployed at 0x742d35...

💰 Deployment Cost Breakdown

Component	Gas Cost	Description
Base Transaction	21,000	Cost for any transaction
Contract Creation	32,000	Base cost for deploying
Code Storage	200 per byte	Storing bytecode on-chain
Total (Typical)	~50,000	For SimpleStorage contract

At 20 Gwei gas price:

50,000 gas × 20 Gwei = 0.001 ETH (~$2 on testnet: FREE!)

🔍 What Happens Under the Hood?

1️⃣

MetaMask Signs Transaction: Your private key signs a transaction containing bytecode + gas payment

2️⃣

Broadcast to Network: Transaction sent to Ethereum nodes via JSON-RPC

3️⃣

Mempool Waiting: Transaction sits in mempool until miner includes it

4️⃣

Miner Executes: Miner runs your bytecode, creates contract at new address

5️⃣

Block Confirmation: Transaction included in block, contract address generated (deterministic)

6️⃣

State Updated: Blockchain state updated, contract code stored permanently

🎯 Common Issues & Solutions

❌ "Insufficient funds"

Solution: Get testnet ETH from Sepolia faucet (sepoliafaucet.com)

❌ "Compilation failed"

Solution: Check syntax errors in Remix console. Fix typos, missing semicolons

❌ "Transaction underpriced"

Solution: Increase gas price in MetaMask settings during deployment

❌ "MetaMask not connecting"

Solution: Refresh page, ensure MetaMask is unlocked, check network selection