Blockchain Engineer (m/f/d)

About Us

We are building a stealth-stage consumer platform that combines AI-powered data extraction, a token-based incentive layer, and on-chain data verification. Our product is a mobile-optimized web application where users contribute verified real-world data and are rewarded with tokens. The proof-of-concept phase is complete, with core components like a barcode scanner, image capture, AI extraction pipeline, and product database already in production. The MVP phase focuses on adding the blockchain and token reward layer.

Your Role

We are seeking an experienced blockchain engineer to take full ownership of the blockchain integration scope for our MVP. This is a hands-on, individual contributor role with direct accountability to the founding team. The engagement is initially for at least five months, with the possibility of an extended relationship based on the MVP phase outcome. You will collaborate closely with the full-stack developer who built our PoC on integration touchpoints and have direct access to the project management team for architectural decisions.

Tasks & Responsibilities

• Smart Contracts: Design, write, and deploy an ERC-20 token contract on Base, with minting restricted to the backend signing wallet.
• Batch Jobs: Implement a Batch Anchor Job (collect unanchored scans, compute hash, submit on-chain) and a Batch Token Distribution Job (multi-send accrued balances to all eligible wallets).
• Backend Integration: Extend the current schema with models for blockchain status, anchor batches, user wallets, and token rewards via a migration that does not disrupt the live extraction pipeline. Build blockchain status and balance API endpoints.
• Frontend Wallet Layer: Integrate wagmi v2 + viem into the existing Next.js frontend. Implement wallet connect/disconnect, token balance display (accrued vs. distributed), and robust error handling for network mismatch, missing extension, and rejected connections. Scanning functionality must remain operational without a connected wallet.
• Security: Ensure backend signing key is managed securely in a secrets manager, implement rate limiting on scan endpoints, avoid raw message signing from user wallets, and establish a documented key rotation runbook before mainnet deployment.
• QA and Load Testing: Extend the regression suite to cover batch flows and blockchain status transitions. Conduct load tests with 500 and 1,000-product anchor batches.

Application Process

We are currently operating in stealth. Candidates who advance to interviews will be required to sign a mutual NDA before full project details are disclosed. To apply, please send your CV and a short cover letter to info@appspoon(dot)io, or connect with Chuanshan Huang on LinkedIn (https://www.linkedin.com/in/chuanshan-huang-617b23115/) for an informal chat.