Blockchain Developer/Architect

Role: Blockchain Developer/Architect Location: New York, NY 10013 / Jersey City, NJ 07310 Position Type: Fulltime Key Responsibilities Design, develop, and deploy Web3 components and integrations for Citi's Digital Asset Platform, including smart contracts, on-chain event listeners, wallet integrations, and blockchain protocol connectors Build and maintain backend services that interface with public and permissioned blockchain networks (e.g., Ethereum, Hyperledger Besu, Corda, or equivalent) Develop, test, and audit smart contracts written in Solidity or equivalent languages, ensuring security, correctness, and gas efficiency Integrate Web3 libraries and SDKs (e.g., Web3J, Web3JS, Ethers.js, Viem) into enterprise Java and/or Node.js backend services Implement asynchronous, event-driven architectures to handle on-chain events, transaction lifecycle management, and blockchain state synchronization Stay current with the rapidly evolving Web3 ecosystem — tracking protocol upgrades, new token standards, Layer 2 solutions, and emerging tooling relevant to institutional use cases Work within Agile/Scrum frameworks, participating in sprint planning, stand-ups, and retrospectives within a distributed global team Qualifications / Experience Bachelor's degree in Computer Science, Engineering, or a related discipline; MS is a plus 8+ years of overall software engineering experience, with a strong backend development foundation Hands-on experience in Web3 and blockchain application development, including smart contract development and blockchain protocol integration Experience with backend development using Java/Spring, Node.js, or equivalent enterprise frameworks Proficiency in Solidity smart contract development, including testing frameworks (Hardhat, Foundry, Truffle) and security best practices Hands-on experience with Web3 libraries such as Web3J, Web3JS, Ethers.js, or Viem Solid understanding of blockchain fundamentals — consensus mechanisms, transaction lifecycle, gas models, wallet infrastructure, and key management Experience with token standards (ERC-20, ERC-721, ERC-1155, ERC-3525, or equivalent) and tokenization patterns Familiarity with permissioned blockchain networks (Hyperledger Besu, Fabric, Corda, or R3) is a strong plus Experience with asynchronous programming, event-driven systems, and message queuing (Kafka, RabbitMQ, or equivalent) Familiarity with DevOps practices, containerization (Docker, Kubernetes), and CI/CD pipelines Understanding of cryptographic concepts — digital signatures, hashing, PKI, and secure key management — as applied to blockchain systems Exposure to Layer 2 scaling solutions (Polygon, Optimism, zkSync, etc.) and cross-chain interoperability protocols is a plus Experience in financial services or regulated industries is a plus Competencies / Skills Web3 Engineering Depth: Strong command of the Web3 technology stack — from smart contract development to on-chain/off-chain integration patterns and blockchain node interaction Backend Engineering Fundamentals: Solid grounding in enterprise software engineering — API design, microservices, data structures, algorithms, and design patterns Security Mindset: Awareness of common smart contract vulnerabilities (reentrancy, front-running, integer overflow, etc.) and best practices for secure on-chain development Curiosity & Adaptability: Genuine enthusiasm for the Web3 ecosystem and the ability to rapidly learn and apply new protocols, standards, and tooling Tooling Proficiency: Working knowledge of engineering tools including Git, Jira, Jenkins, Hardhat/Foundry, Docker, Helm, and observability platforms When applying, mention the word CANDYSHOP to show you read the job post completely.