Blockchain Developer

**Location:** Remote / India **Engagement:** Project-Based Contract (6–10 weeks) **Company:** TopCrop – Export supply-chain traceability for global agri buyers **About the Role** TopCrop is building a **Polygon-based traceability platform** for agricultural exports. This is a **project-based, delivery-driven contract** to build smart contracts + core backend integration for our MVP. If you know how to ship production-ready blockchain systems fast — you’ll fit right in. **What You’ll Own** **Smart Contract Development** - Design & implement lifecycle contracts for batches, QC records, and shipment events on **Polygon** testnet/mainnet. - Create on-chain mapping for QR codes, IPFS hashes, and verification endpoints. - Optimize gas + security. **Blockchain & IPFS Integrations** - Implement IPFS pinning for QC documents and metadata (Pinata / n8n). - Product Requirements Document - Integrate smart contracts with backend APIs (Hasura/PostgREST). **Backend & API Hooks** - Build webhook triggers for batch.created, qc.completed, and shipment.status\_changed events. - Work with REST/GraphQL API design and business logic. **Testing & Deployment** - Write automated tests (Hardhat). - Deploy contracts using Infura/Alchemy. - Support CI/CD and QA pipeline setup. **Qualifications** - Strong Solidity experience — deployed real contracts on testnet/mainnet. - Hands-on with **Polygon** , Hardhat, IPFS, RPC endpoints. - Experience integrating blockchain with **PostgreSQL, Hasura, REST/GraphQL APIs** . - Clear understanding of gas optimization, security patterns, audit basics. - Ability to work independently on fast timelines. **Nice to Have** - Experience with n8n, Retool, React Admin. - Previous work on supply-chain or traceability systems. - Familiarity with QR-based verification flows. **Timeline** This is a **project-based contract** (approx. **8 weeks** , aligned with TopCrop’s development plan). Work is milestone-structured and output-driven. **What We Offer** - Competitive project fee (milestone-based). - Chance to build a real impact product used by global export buyers. - Opportunity for long-term collaboration after MVP.