Blockchain Developer

7+ Years of exp

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

• Collaborate with architects and senior engineers to contribute to the design of scalable, secure, and resilient Web3 infrastructure

• Participate in code reviews, providing and receiving constructive technical feedback to maintain high engineering standards

• Support the integration of digital asset custody solutions, tokenization frameworks, and DeFi/Trad Fi bridging components

• Contribute to technical documentation, including smart contract specifications, integration guides, and architecture notes

• 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

• Help identify and resolve technical issues across the Web3 stack, escalating where appropriate to ensure delivery quality and timelines

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

• 2 to 4 years of hands-on experience in Web3 and blockchain application development, including smart contract development and blockchain protocol integration

• 3 to 5 years of 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 Dev Ops 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

• Familiarity with Agile/Scrum methodologies and distributed team collaboration tools

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

• Collaborative Spirit:
  Strong team player who communicates clearly and constructively with engineers, architects, and non-technical stakeholders

• Delivery Orientation:
  Ability to manage personal delivery commitments, prioritize effectively, and produce high-quality output within sprint cycles

• Attention to Detail:
  Rigorous approach to testing, code quality, and documentation - particularly important given the immutable nature of on-chain deployments

• Tooling Proficiency:
  Working knowledge of engineering tools including Git, Jira, Jenkins, Hardhat/Foundry, Docker, Helm, and observability platforms