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Project Context Carma Earth is building CCX (Carbon Carma Exchange), a platform to provide transparent, auditable records of carbon credit transactions. We have a requirement for a pilot project working along side a hedera hasgraph off chain smart contract = seller-side platform (escrow, custody, smart features). Carma = public proof layer, not custodian. Our role is to record confirmed Hashgraph transactions onto Polygon for immutable auditability. This is not a full live bridge. It is a one-off migration process (MVP) where Carma simply publishes hedera-confirmed transactions onto our Polygon smart contracts. Scope of Work 1. Input & Data Handling Accept transaction data exported from Hashgraph Required fields *to be agreed: transactionID, projectID, buyerRef, tonnes, date, certificateHash (cross-ref to Orbex record), sourceSystem. Validate and transform input into canonical JSON schema (developer to propose final schema). 2. Smart Contract Interaction (Polygon) Create Carma1155.sol contract. Functions required: issueBatch → Mint tokens representing Hedera transaction. retire → Retire tokens when Hashgrah marks credits retired. Sandbox testing required before production deployment. Final deployment must use Carma’s custodial wallet (not developer’s). 3. Metadata & Storage Record canonical JSON metadata in IPFS/S3. Store resulting hash on Polygon alongside the token action (mint/retire). 4. Proof Layer Generate a PDF certificate for each transaction. Certificate includes transaction details and QR code linking to Polygonscan. Certificates must be easily retrievable by RGE buyers, auditors, and stakeholders. Flexibility to support batch certificates in future (not MVP). 5. Outputs Immutable Polygon transaction (mint or retire). IPFS/S3 metadata record. PDF certificate with QR → Polygonscan link. Simple script/service for repeatable process (manual trigger acceptable for MVP). Out of Scope (MVP) Live API integration (manual CSV/JSON ingestion only). Wallet UX or end-user interfaces. Extended smart contract functionality beyond issueBatch + retire. Compliance/payment system integrations Deliverables Input pipeline (CSV/JSON → canonical JSON). Polygon contract calls (mint/retire) using Carma1155. (will seek advice) Metadata storage in IPFS/S3, hash reference on Polygon. Certificate generation service (transaction + QR → Polygonscan). Documentation (deployment steps, sample input/output, certificate template). Sandbox demo + production-ready code. Success Criteria Transactions from Hashgraph can be minted/retired on Polygon within Carma1155. Every record has corresponding JSON metadata and IPFS/S3 hash. Certificates generated per transaction are verifiable via Polygonscan. No double-minting or mismatch between Hashgraph and Polygon data. Code is lightweight, auditable, and maintainable by Carma. Timeline Phase 1 (Week 1): Define JSON schema, set up sandbox testing. Phase 2 (Week 2): Implement contract calls, metadata storage, certificate generation. Phase 3 (Week 3): End-to-end testing with Hashgraph sample data. Deliverable: MVP deployment on Carma Polygon by end of Week 3. Required Expertise Solidity smart contract interaction (ERC-1155). IPFS/S3 integration for metadata. Certificate/QR code generation. API/data transformation (CSV/JSON). Blockchain deployment (Polygon, custodial wallet governance).