Blockchain Software Developer

Salary: £62,000 - 102,000 per year

Requirements:

• Bachelors degree in Computer Science, Engineering, or a related discipline; a masters degree is a plus
• Extensive overall software engineering experience with a strong backend development foundation
• Proven hands-on experience in Web3 and blockchain application development, including smart contract development and blockchain protocol integration
• Solid experience with backend development using Java/Spring, Node.js, or equivalent enterprise frameworks
• Proficiency in Solidity smart contract development, including testing frameworks such as Hardhat, Foundry, or Truffle, and security best practices
• Hands-on experience with Web3 libraries such as Web3J, Web3JS, Ethers.js, or Viem
• Solid understanding of blockchain fundamentals, including consensus mechanisms, transaction lifecycle, gas models, wallet infrastructure, and key management
• Experience with token standards such as ERC-20, ERC-721, ERC-1155, ERC-3525, or equivalent, and tokenization patterns
• Familiarity with blockchain networks such as Hyperledger Besu, Solana, or Canton is a strong plus
• Experience with asynchronous programming, event-driven systems, and message queuing such as Kafka or RabbitMQ
• Familiarity with DevOps practices, containerization such as Docker and Kubernetes, and CI/CD pipelines
• Understanding of cryptographic concepts such as digital signatures, hashing, PKI, and secure key management as applied to blockchain systems
• Exposure to Layer 2 scaling solutions 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
• Strong command of the Web3 technology stack, from smart contract development to on-chain/off-chain integration patterns and blockchain node interaction
• Solid grounding in enterprise software engineering, including API design, microservices, data structures, algorithms, and design patterns
• Awareness of common smart contract vulnerabilities and best practices for secure on-chain development
• Genuine enthusiasm for the Web3 ecosystem and the ability to rapidly learn and apply new protocols, standards, and tooling
• Strong team player who communicates clearly and constructively with engineers, architects, and non-technical stakeholders
• Ability to manage personal delivery commitments, prioritize effectively, and produce high-quality output within sprint cycles
• Rigorous approach to testing, code quality, and documentation
• Working knowledge of engineering tools including Git, Jira, Jenkins, Hardhat/Foundry, Docker, Helm, and observability platforms

Responsibilities:

• Design, develop, and deploy Web3 components and integrations for our 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
• Develop, test, and audit smart contracts written in Solidity or equivalent languages, ensuring security, correctness, and gas efficiency
• Integrate Web3 libraries and SDKs into our 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 design scalable, secure, and resilient Web3 infrastructure
• Participate in code reviews and provide constructive technical feedback
• Support the integration of digital asset custody solutions, tokenization frameworks, and DeFi/TradFi bridging components
• Contribute to technical documentation, including smart contract specifications, integration guides, and architecture notes
• Stay current with the evolving Web3 ecosystem, including protocol upgrades, new token standards, Layer 2 solutions, and emerging tooling relevant to institutional use cases
• Work within Agile/Scrum frameworks and participate 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

Technologies:

• API
• Backend
• Blockchain
• CI/CD
• DevOps
• Docker
• Git
• Helm
• Support
• JIRA
• Java
• Jenkins
• Kafka
• Kubernetes
• RabbitMQ
• Security
• Solidity
• Spring
• Web3
• microservices
• NodeJS
• Ethereum

More:

We are Citi, a global organization of more than 230,000 people, and we are building our Citi Integrated Digital Assets Platform engineering team in London. This is a hands-on role focused on the intersection of decentralized technologies and institutional finance, where you will help us design and deliver production-grade Web3 infrastructure for tokenization, smart contracts, on-chain settlement, and blockchain integrations. You will join a collaborative, globally distributed team of engineers, architects, and business technologists, with access to continuous learning, internal innovation programs, and the opportunity to make a real impact on the future of digital finance. In London, we offer a business casual workplace with a hybrid working model of up to 2 days working from home per week, a competitive base salary reviewed annually, 27 days of annual leave plus bank holidays, discretionary performance bonus, private medical care and life insurance, an employee assistance program, pension plan, paid parental leave, employee discounts, and learning and development resources. We are committed to an inclusive workplace where everyone can thrive.

last updated 34 week of 2026