FailoverX

This project combines AI-powered transaction routing with cross-chain failover to help users save on gas costs and ensure reliable transaction execution.

The Smart Transaction Scheduler allows users to schedule blockchain transactions with intelligent failover mechanisms. When a transaction fails or gas prices spike on the primary chain, the system automatically routes to cheaper alternatives like Base, Arbitrum, or Hedera.

Key features:

• AI-powered PKPs (Programmable Key Pairs) via Lit Protocol's Vincent SDK for automated transaction signing
• Cross-chain balance aggregation using Avail Nexus SDK
• Hedera integration as ultra-low-cost fallback chain ($0.0001 gas)
• Real-time gas monitoring and intelligent chain selection
• Automated failover across Ethereum, Base, Arbitrum, Optimism, and Hedera
• Secure distributed key management - keys never exist in full anywhere

Users connect their wallet, create an AI-powered PKP, schedule a transaction with preferred chains, and the system handles optimal routing and automatic failover if the primary chain fails. This prevents failed transactions and saves users money through intelligent gas optimization.

Frontend Stack:

• React 19 + TypeScript + Vite for modern, fast development
• TailwindCSS v4 + shadcn/ui for beautiful, responsive UI
• Wagmi v2 + Viem for Ethereum wallet integration
• Zustand for state management
• React Router v7 for navigation

Blockchain Integration:

• Lit Protocol Vincent SDK (@lit-protocol/vincent-app-sdk v2.2.3) - AI-powered PKP creation with OAuth authentication using App ID 1339828260
• Avail Nexus SDK (@avail-project/nexus-core v0.0.7-beta.0) - Unified cross-chain balance queries and data aggregation
• Hedera SDK (@hashgraph/sdk v2.75.0) - Ultra-low-cost transaction execution
• Ethers.js v5 for contract interactions
• OpenZeppelin contracts for security (ReentrancyGuard, Ownable)

Smart Contracts:

• Solidity 0.8.19 with Hardhat development environment
• SmartTransactionScheduler.sol - Main contract with failover logic (400+ lines)
• Deployed across Sepolia, Base Sepolia, Arbitrum Sepolia, Optimism Sepolia
• Hedera testnet integration for fallback execution

Key Technical Innovations:

1. Vincent AI Integration - We use the official Vincent SDK's getWebAuthClient() with our registered App ID (1339828260) to create AI-powered PKPs that can intelligently route transactions and make automated failover decisions.

2. Avail Nexus for Cross-Chain Coordination - The Nexus SDK aggregates balances across all supported chains in real-time, enabling users to see their total liquidity and make informed decisions about which chain to use.

3. Hedera as Ultimate Fallback - When Ethereum L2s experience congestion, Hedera provides 3-5 second finality at $0.0001 per transaction, ensuring transactions always execute.

4. Event-Driven Architecture - Smart contract emits CrossChainExecutionRequested events that trigger the frontend to use Avail Nexus SDK for asset bridging, then execute on the target chain.

Notable Hacks:

• Custom TypeScript service layer abstracts all three SDKs (Vincent, Avail, Hedera) into a unified transaction scheduling API
• Static gas estimates in the contract for demo purposes, with hooks for dynamic oracle integration
• Modular failover system allows adding new chains without contract redeployment
• Browser-based PKP creation flow with MetaMask integration for seamless UX