SwapStarter - Learning Blockchain DEX Development

A full-stack decentralized exchange (DEX) built from scratch to learn blockchain development.

🎯 Learning Journey

Phase 1: Wallet Connection ✅

• Implemented wallet connection with RainbowKit
• Network switching and balance display
• Multi-wallet provider support

Phase 2: ERC20 Tokens ✅

• Created SwapToken (ERC20) with mint/burn
• Deployed to Sepolia testnet
• Comprehensive test suite (7 tests)
• Frontend integration for viewing/transferring

Phase 3: AMM Swap Contract ✅ JUST COMPLETED

• Implemented constant product formula (x × y = k)
• Liquidity pool with add/remove functionality
• Token swaps with slippage protection
• Deployed with 1000 TKA + 1000 TKB initial liquidity
• Solved real-world SafeERC20 compatibility issue

📊 Deployed Contracts (Sepolia)

Contract	Address	Etherscan
Token A (TKA)	0xd4F8...7374	View
Token B (TKB)	0xb8c1...fC6d	View
SimpleSwap	0x1286...4706	View

🛠️ Tech Stack

Smart Contracts:

• Solidity ^0.8.20
• Foundry (testing & deployment)
• OpenZeppelin contracts

Frontend:

• Next.js 14 (App Router)
• TypeScript
• wagmi & viem
• RainbowKit
• TailwindCSS

🧪 Key Learnings

AMM Mathematics

Constant Product: x × y = k
Example: 1000 TKA × 1000 TKB = 1,000,000
Swap 100 TKB → Get 90.91 TKA
New: 909.09 TKA × 1100 TKB = 1,000,000 ✓

Real-World Issues Solved

• SafeERC20 Compatibility: Debugged and fixed transfer issues
• Allowance Management: Proper approve/transferFrom flow
• Gas Estimation: Understanding transaction costs
• State Synchronization: Keeping frontend in sync with blockchain