Starlink

Starlink is a next-generation, trustless, bidirectional cross-chain swap protocol bridging Ethereum and Stellar, building on 1inch’s Fusion+ architecture. It combines on-chain hashlock/timelock guarantees with off-chain auction dynamics to deliver truly atomic, no-custodian swaps, no wrapped tokens, no third-party custodians, and no hidden intermediaries.

Core Innovations

• 10-Contract HTLC Sharding: Each swap amount is split into 10 discrete HTLCs, each holding 10% of the funds. This lets multiple resolvers participate concurrently, claiming 10%, 20%, or any combination, enabling ultra-flexible partial fills.

• Dutch-Auction Resolver Marketplace: Resolvers observe open swaps and submit bids off-chain. As the auction price ticks down, the first resolver to bid at or below their target price locks in their tranche. This competitive mechanism drives down costs and maximizes liquidity.

• Multi-Resolver Support: Instead of “winner takes all,” Starlink allows several resolvers to fill a single swap in parallel, each handling a slice. This both improves throughput and distributes risk, since no single node bears the entire order.

• Atomic Cross-Chain Execution: All HTLC contracts, and their Stellar counterparts, use the same SHA-256 hashlock and synchronized timelocks. Funds on both chains can only be claimed with the secret preimage, guaranteeing that either both sides settle or both time out and refund.

• No Custodians, No Wrappers: True peer-to-peer exchange: assets lock in native HTLC contracts on each chain. Settlement is fully decentralized, verifiable on-chain, and immune to custodial failures.

• Real-Time Settlement: As soon as the user claims a Stellar contract and reveals the preimage, resolvers immediately claim the corresponding smart contract, achieving near-instantaneous finality across chains.

• 10-contract HTLC Sharding: Splitting swaps into 10 HTLCs gives a balance between granularity and simplicity. But Starlink’s architecture is infinitely scalable, for mega-swaps or institutional use, you could shard a single order into hundreds of micro-HTLCs, each representing 0.1% or 0.01% of the total. This dramatically reduces per-fill gas costs and lets dozens of resolvers bid concurrently, smoothing out large liquidity demands. Future versions could auto-tune the number of shards based on order size and network congestion, maximizing fill speed and minimizing fees.

Starlink is built using a modern, full-stack architecture with the following key technologies: Smart Contracts (Solidity)

• TestEscrowFactory.sol: Main factory contract that creates 10 separate HTLC contracts for each swap
• HTLC.sol: Individual hash time-locked contract implementation with claim/refund functionality
• Resolver.sol: Manages resolver bidding and contract assignment
• IERC20.sol: Standard ERC20 interface for token support

The 10-contract system enables multiple resolver participation where each contract represents exactly 10% of the total swap amount. Multiple resolvers can claim different contracts based on their fill percentage (10%, 20%, 30%, etc.), creating a competitive marketplace and ensuring no single resolver needs to fill the entire swap.

Backend (Node.js/Express) RESTful API: Clean endpoints for swap initiation, locking, claiming, and status tracking Database Integration: SQLite for persistent swap state management Blockchain Services: Direct integration with Ethereum (Sepolia) and Stellar testnets Resolver Service: Automated Dutch auction system with competitive bidding Stellar Service: Stellar blockchain integration for XLM operations

The backend implements a sophisticated resolver system that: Manages automated Dutch auctions for optimal pricing Tracks 10-contract distribution and claiming Handles cross-chain transaction coordination Provides real-time swap status updates Enables multiple resolvers to fill the same swap

Frontend (React/Vite) Modern UI: Clean, responsive interface built with React and Tailwind CSS Real-Time Updates: Live auction status and swap progress tracking Wallet Integration: Seamless MetaMask and Stellar wallet connections Context Management: React Context for global state management Error Handling: Comprehensive error boundaries and user feedback

Key Technical Innovations Multiple Resolver System:

• Multiple resolvers can participate in a single swap
• Each resolver claims specific contracts based on their capacity
• Enables partial fills (10%, 20%, 30%, etc.)
• Creates competitive marketplace for better pricing

10-Contract HTLC System:

• Breaks each swap into exactly 10 contracts
• Each contract = 10% of total amount
• Enables granular control over swap execution
• Prevents single-point-of-failure issues

Dutch Auction Mechanism:

• Automated resolver bidding system
• Real-time price discovery
• Competitive pricing for users
• Percentage-based fill distribution

Cross-Chain Atomic Swaps:

• Hashlock verification on both chains
• Timelock enforcement for security
• No custodians or wrapped assets
• Trustless execution

Real-Time Settlement:

• Immediate asset transfer upon verification
• Multi-resolver coordination
• Transaction status tracking
• Error recovery mechanisms

Partner Technologies Used 1inch Fusion+: Leveraged for offchain order execution on Ethereum Ethereum Sepolia Testnet: For ETH contract deployment and testing Stellar Testnet: For XLM operations and HTLC implementation MetaMask: For Ethereum wallet integration Stellar SDK: For Stellar blockchain operations

Notable Technical Achievements

• Multiple Resolver Architecture: Built a system where multiple resolvers can fill different portions of the same swap, creating a competitive marketplace
• Partial Fill Capability: Resolvers can claim 10%, 20%, 30%, etc. of the total swap amount, enabling flexible participation
• Automated Resolver Network: Built a sophisticated bidding system that automatically optimizes pricing through competition
• Cross-Chain Coordination: Successfully synchronized operations across two different blockchain networks
• Real-Time Auction System: Implemented live bidding with immediate execution

The system demonstrates advanced blockchain interoperability, combining the security of Ethereum smart contracts with the speed and low cost of Stellar transactions, while enabling multiple resolvers to participate in swaps through partial fills, creating a seamless and competitive cross-chain swap experience.

GitHub Repositories The project is contained in a single comprehensive repository with the following structure: Smart Contracts: contracts/ - Solidity contracts for HTLC and factory system Backend API: backend/ - Node.js/Express server with blockchain integration Frontend UI: frontend/ - React application with real-time auction interface