The problem FriendSwap solves

FriendSwap Miniapp - P2P Cross-Chain Token Swaps

Project Overview

Name: FriendSwap
Title: Decentralized P2P Cross-Chain Token Exchange on Farcaster
Category: DeFi Infrastructure / Cross-Chain Protocol

Description

FriendSwap is a peer-to-peer cross-chain token swap protocol that enables users to exchange tokens directly across different blockchain networks without relying on centralized exchanges or bridges. Built as a Farcaster Mini App, it combines the social aspect of Farcaster with trustless cross-chain DeFi functionality, allowing users to discover and fulfill swap requests within their social network.

The protocol implements atomic cross-chain swaps using hashlock and timelock mechanisms, ensuring that either both parties receive their tokens or the swap fails completely - eliminating counterparty risk.

What We're Solving

1. Peer-to-Peer Token Exchange Risk

• People hold different tokens but have no safe way to exchange them directly
• Example: Alice has USDC and needs ETH, Bob has ETH and needs USDC
• Current solutions involve centralized exchanges with custody risks and fees
• No trustless platform for direct one-to-one token swaps between individuals

2. Cross-Chain Liquidity Fragmentation

• Traditional DEXs are limited to single chains
• Users must use complex bridge protocols with high fees and risks
• Limited liquidity across different blockchain ecosystems

3. Centralized Exchange Dependencies

• Users rely on CEXs for cross-chain trades
• Custody risks and regulatory concerns
• High fees and withdrawal limits

4. Social Discovery Gap

• No easy way to find trusted counterparties for OTC trades
• Lack of social context in DeFi transactions
• Difficulty in discovering fair swap opportunities

5. Complex User Experience

• Multi-step bridge processes
• High technical barriers for cross-chain operations
• Poor mobile/social media integration

How It Works

Core Protocol Architecture

Step-by-Step Process

1. Request Creation: Asker creates a swap request specifying:

   • Source token and amount (what they're offering)
   • Destination token and amount (what they want)
   • Source and destination chains
   • Expiration time

2. Source Escrow Deployment: Asker deploys and funds the source escrow contract with their tokens

3. Discovery: Other users browse available swaps on the Farcaster Mini App

4. Fulfillment: Fulfiller deploys destination escrow with their tokens matching the request

5. Secret Revelation: The relayer reveals the secret, enabling both parties to claim their tokens atomically

6. Completion: Both escrows release tokens to the respective recipients

Security Mechanisms

• Hashlock: Cryptographic commitment ensuring only the secret holder can unlock funds
• Timelock: Time-based expiration allowing refunds if swaps aren't completed
• Deterministic Addresses: Predictable contract addresses for verification
• Access Control: Only authorized parties can deploy and interact with escrows

Why This Product Matters

1. Democratizing Cross-Chain DeFi

• Removes technical barriers for average users
• Social context makes DeFi more accessible and trustworthy
• Mobile-first approach reaches broader audience

2. True Decentralization

• No central authority or custody
• Peer-to-peer discovery and execution
• Trustless atomic swaps

3. Cost Efficiency

• Direct swaps without intermediate bridges
• Minimal gas costs through optimized contracts
• No trading fees beyond platform maintenance

4. Social Layer Innovation

• First P2P cross-chain protocol integrated with social media
• Leverages social graphs for counterparty discovery
• Community-driven liquidity provision

5. Native Notification System

• Farcaster provides built-in notification infrastructure
• Users get real-time alerts when new swap opportunities match their interests
• Push notifications for swap fulfillment requests directly in their social feed
• Perfect platform for discovering time-sensitive trading opportunities within your network

Challenges I ran into

Technical Challenges Overcome

1. Cross-Chain State Synchronization

Challenge: Ensuring atomic operations across different blockchains with different finality times.

Solution: Implemented hashlock-timelock pattern with deterministic contract addresses and event-driven relayer coordination.

2. Minimal Proxy Gas Optimization

Challenge: Deploying individual escrow contracts for each swap is expensive.

Solution: ERC-1167 minimal proxy pattern reduces deployment costs by ~90% while maintaining isolated state.

3. Factory Initialization with Clones

Challenge: Constructor parameters don't work with cloned contracts.

Solution: Implemented initialize() pattern with factory address setting during first call to maintain access control.

Smart Contract Address(es)

Contract Addresses

Sepolia

• Factory: 0x543046076dE28686b3A6BEb34a29C747F26fBA23
• EscrowSrc: 0x976708a30358649CbFaDcFb4583518556bb4699E
• EscrowDst: 0x8DCB7fC8e4BB2bb5c5cB70b5F1a22035d6D79FFe

Base Sepolia

• Factory: 0xEC9f35Dc7B6bC272Dc874Ae016554FcEBce5f68b
• EscrowSrc: 0xE80a47Ff3C587087Ac2809b82C5ca1d29196cc24
• EscrowDst: 0x4951715141dED8b45a01529e98dC26d24B3da5a0