PayCrossChain

PayCrossChain is a comprehensive multi-chain crypto payment and investment platform that solves fragmentation in DeFi by unifying cross-chain payments, yield optimization, and conditional routing in one seamless mobile experience.

Our app leverages 1inch Fusion+ for efficient cross-chain swaps without manual bridging, Circle's CCTP V2 for ultra-fast USDC transfers across chains, and Beefy Finance vaults for automated yield generation. Users can create conditional payment preferences, routing funds to different wallets based on amount, token type, or time constraints.

The platform includes a Nodit-powered portfolio dashboard for comprehensive analytics, gas payment in USDC instead of native tokens, and sophisticated vault investments across Ethereum, Polygon, Avalanche, Base, Arbitrum, and Celo networks.

PayCrossChain eliminates the complexity of managing crypto across multiple chains, allowing users to pay anyone, anywhere, on any chain while automatically optimizing their idle assets for yield.

PayCrossChain is built with a modern tech stack that combines React Native (Expo) for cross-platform mobile development with Solidity 0.8.27 for smart contracts.

The frontend implements a comprehensive navigation flow with tab-based primary navigation and stack-based secondary navigation. We use Context API for global state management, AsyncStorage for local persistence, and IPFS for decentralized preference storage.

For blockchain interactions, we integrated:

1. 1inch Fusion+: We leverage their API for gasless cross-chain swaps through the combination of Limit Orders and aggregated liquidity. This eliminates the need for users to manually bridge tokens.

2. Circle's CCTP V2: Our implementation uses Circle's Cross-Chain Transfer Protocol for seamless USDC transfers across supported networks. We built custom smart contracts that interact with CCTP's TokenMessenger and MessageTransmitter.

3. Beefy Finance: We created an InvestmentVaultsAdapter contract that interfaces with Beefy vaults, allowing users to deposit into auto-compounding strategies while abstracting away the complexity.

4. Nodit Web3 Data API: Used for comprehensive portfolio tracking and transaction history across multiple chains.

5. ENS Integration: For human-readable identities, reducing the friction of cross-chain payments.

One particularly innovative implementation is our conditional payment routing system, which stores user preferences on IPFS (via Pinata) with EIP-712 signatures for authenticity. This system allows payments to be intelligently routed based on complex conditions while keeping gas costs minimal.

For performance optimization, we implemented memoization for expensive calculations, batch updates for state changes, and intelligent caching for API calls to external services.

The architecture follows a modular design with clear separation of concerns between payment systems, investment vaults, and group expense tracking. This makes the codebase maintainable and allows for future expansion to additional chains and protocols.