X3Fusion

This Project won the 1st Prize in the Near Track of ETHGlobal Unite-Defi Hackathon

X3Fusion is a cross-chain swap extension built on top of the 1inch Fusion+ framework, enabling seamless, trustless atomic swaps between Ethereum, NEAR, and Tezos. By combining on-chain HTLC logic, dynamic factory patterns, and an off-chain resolver API, X3Fusion abstracts away network-specific complexities and delivers a unified developer experience for building robust cross-chain applications.

Features

These are the contract addresses for the relevant chains.

Near Escrow Factory: escrowfac22.testnet
Near Dutch Auction: dutchauction22.testnet
Tezos Escrow Factory: KT18g1YSPAy9dTehdPVaAfSuESvP3p27HeQs
Tezos Escrow Ex: KT1D9qehRdgVzEv1FgPNESB1DnxdekSdNbHN
EVM Escrow Factory: 0x49ae5957c37f993667c676dcfad35cfAa9Fbc563
EVM Dutch Auction: 0xC3deF82aD7C16299b60C792B3c92D29DDB4e9485 (Calculator)
EVM Order Filler: 0x4B4c97f5B98e22160d4D5582865a218308a084bA

• Atomic Cross-Chain Swaps: Trustless value transfers between ETH, NEAR, and Tezos using Hash Time-Locked Contracts (HTLCs).
• Dynamic Factory Pattern: On-demand deployment of escrow contracts tailored to each swap’s parameters.
• Dutch Auction Support: Custom price-curve logic to handle partial fills and efficient order matching on Tezos inspired from the Dutch Auction is LOP.
• Unified Resolver API: Single RESTful interface to orchestrate auctions, deployments, and withdrawals across networks.
• 1inch-Inspired EVM Escrows: Proven Solidity contracts adapted to X3Fusion’s order schema for gas-efficient settlements.
• Rust & SmartPy Tooling: Native NEAR Rust SDK integration and SmartPy-based Tezos contracts for rapid development and strong type safety.

How It Works

X3Fusion’s cross-chain swap logic is built on three specialized on-chain modules and a single off-chain Resolver API:

1. Auction Phase

   • Create or fill a Dutch-auction order on the source chain (Ethereum or Tezos).
   • Secret hashlocks and order parameters (amount, expiry, curve) are registered on-chain.

2. Deployment Phase

   • Resolver calls the appropriate endpoint to deploy a new HTLC escrow on the destination chain:
     • POST /deploy/evm
     • POST /deploy/near
     • POST /deploy/tezos

3. Monitoring & Secret Reveal

   • Resolver listens for on-chain events signaling the secret preimage reveal.

4. Withdrawal Phase

   • Once the secret is detected, the resolver finalizes the swap by invoking the correct withdrawal endpoint:
     • POST /withdraw/evm
     • POST /withdraw/near
     • POST /withdraw/tezos

Resolver API Endpoints

The SwapPage.tsx file is the one that manages the API's and acts as the resolver.

Future Enhancements

-- Merkle Tree Secret Resolution: Implement a Merkle-tree-of-secrets scheme to allow efficient, secure partial fills without exposing all preimages at once. Participants can prove knowledge of specific leaf preimages, preserving confidentiality and enabling granular withdrawals.

-- Multi-Hop Swaps: Extend resolver logic to coordinate atomic swaps across more than two chains in a single transaction flow.

-- Enhanced Monitoring Dashboard: Build a real-time UI to track orders, deployments, and settlements across all supported networks.