PyHard

PyHard is a comprehensive crypto wallet ecosystem designed to make blockchain accessible to non-technical users through gasless transactions, QR code payments, social features, and family banking. The system consists of six core components working together: a main mobile wallet app, a child app for family members, a Cloudflare Worker paymaster for gas sponsorship, a React SDK for vendor integration, a documentation website, and smart wallet contracts. The ecosystem enables users to send PYUSD payments without ever paying gas fees, manage family sub-accounts with spending limits, and create recurring subscriptions to vendors. Users can start using PyHard without any crypto wallet - just sign up with email or social accounts and embedded wallets are created automatically via Privy. Vendors can easily integrate payment acceptance through QR codes and subscription management. The entire system is built on Arbitrum with PYUSD integration, using EIP-7702 delegation for advanced account abstraction that enables truly gasless transactions. The mobile app provides a PayPal-style user experience with balance management, transaction history, and social payment features. The child app allows parents to create sub-wallets for family members with controlled spending limits and parental oversight. The vendor SDK enables businesses to accept payments and manage subscriptions with minimal integration effort. The system addresses the core problem of gas fees making small recurring payments impractical on blockchain. Traditional subscriptions require users to pay gas for every payment, eating into the subscription value and creating complex UX that discourages adoption. PyHard solves this by using EIP-7702 to delegate transaction execution to a paymaster, enabling truly gasless subscriptions with one-time authorization for recurring payments. The result is a complete ecosystem that makes crypto payments as simple as traditional payment methods while maintaining the security and decentralization of blockchain technology. Users enjoy zero gas fees, simple QR code-based onboarding, and family banking features, while vendors get easy integration and automated payment processing.

The project uses React Native with Expo for the mobile applications, providing cross-platform functionality for both the main wallet and child app. The main app integrates Privy for seamless walletless onboarding and wallet creation, while the child app uses Viem for direct blockchain interactions. Both apps handle PYUSD transactions and QR code generation for payments and subscriptions. The gas sponsorship system is implemented as a Cloudflare Worker using TypeScript and Viem for Ethereum interactions. This paymaster validates EOA signatures and sponsors gas for all PYUSD Smart Wallet transactions using EIP-7702 delegation. The worker includes rate limiting, whitelist management, and comprehensive error handling to prevent abuse while maintaining security. The smart wallet contracts are built with Solidity using Hardhat for development and testing. The core SmartWallet contract implements account abstraction with subscription management, sub-wallet functionality, and family banking features. The system uses OpenZeppelin contracts for security and includes EIP-7702 delegation for gas sponsorship. The vendor SDK is a React TypeScript package that provides both styled and headless components for easy integration. It uses Wagmi and Viem for blockchain interactions, Reown AppKit for wallet connection, and includes real-time payment detection through Blockscout API polling. The SDK supports both manual address input and wallet connection for maximum flexibility. The documentation website is built with Next.js 14 using the App Router, featuring comprehensive documentation, interactive demos, and integration guides. The site uses Tailwind CSS for styling and integrates the vendor SDK as a local package for live demonstrations. The entire system integrates PYUSD as the primary stablecoin, with the paymaster sponsoring all gas fees to create a truly gasless experience. The EIP-7702 implementation allows EOAs to delegate execution to smart contracts, enabling the paymaster to sponsor transactions while maintaining user control and security. The system uses Blockscout for transaction monitoring and payment detection, providing real-time updates across all components. The architecture enables seamless integration between all components, with the mobile apps connecting to smart wallets, the paymaster sponsoring transactions, and the vendor SDK providing easy integration for businesses. The result is a complete ecosystem that makes crypto payments as simple as traditional payment methods while maintaining the security and decentralization of blockchain technology.