Role overview We’re looking for a highly experienced Web3 / Blockchain Engineer to build and maintain the smart contract and backend infrastructure that powers ScaleIn. You will design upgradeable, gas‑efficient contracts, implement trustless marketplace mechanics (escrow, auctions, royalties), and integrate on‑chain logic with our APIs, storage, and front‑end systems. This is a hands‑on role that requires strong Solidity expertise, production backend experience (TypeScript/Node.js or Go), and practical knowledge of L2 rollups, bridging, and wallet integrations.
What you’ll ship (Phase I focus) - Production‑grade smart contracts for minting (ERC‑721 / ERC‑1155), royalties, marketplace listings, and escrow. - Gas optimization and L2 deployment strategy (Polygon + rollups) to minimize user costs. - Secure upgradeable contract patterns (proxy / upgradeable frameworks) with automated tests and CI. - RESTful / GraphQL APIs that integrate on‑chain events with front‑end and indexing services. - Wallet integrations (MetaMask, WalletConnect) and hardware wallet compatibility (Ledger/Trezor). - Basic KYC flow integration, audit logging, and admin tooling to support compliance requirements.
Responsibilities - Architect, design, and implement smart contracts and backend services for minting, listing, bidding, and settlement. - Write comprehensive unit/integration tests and maintain CI pipelines (Hardhat/Foundry/Truffle + test frameworks). - Optimize contracts for gas and support Layer‑2 rollups or sidechains for cost‑effective finality. - Integrate off‑chain systems: IPFS / S3 media storage, PostgreSQL indexing, Elasticsearch for search, Kafka event buses, and caching (Redis). - Collaborate with front‑end engineers to deliver seamless wallet UX and real‑time bid/auction updates (WebSockets). - Implement secure key management, support hardware wallets, and follow best practices for secret handling. - Participate in security reviews, pen‑tests, and coordinate third‑party smart contract audits. - Help define operational runbooks, observability (Prometheus / Grafana / ELK), and scalability strategies (Kubernetes autoscaling).
Required qualifications - 2+ years professional blockchain development experience; 3+ years general software engineering experience preferred. - Deep expertise in Solidity, smart contract design patterns, ERC‑721 & ERC‑1155 standards, and upgradeable proxies (OpenZeppelin or equivalent). - Proven experience deploying and maintaining contracts on Ethereum and Polygon (or equivalent L1/L2 networks). - Strong backend experience with TypeScript/Node.js or Go, building REST/GraphQL APIs and integrations. - Practical knowledge of Layer‑2 solutions, rollups, bridges, and gas‑optimization strategies. - Experience with developer tooling: Hardhat, Foundry, Truffle, Ethers.js, Web3.js. - Solid automated testing and CI experience; familiarity with security best practices and audit remediation. - Experience integrating wallets (MetaMask, WalletConnect) and hardware wallets (Ledger/Trezor). - Comfortable with Docker, Kubernetes, cloud environments (AWS/GCP), PostgreSQL, Redis, and Elasticsearch. - Strong product and communication skills — able to translate technical constraints into product tradeoffs.
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