Blockchain Software Developer - Digital Assets Platform

Citi; Greater London; On-site; GBP 90,000 - 120,000; Full time

Job summary

Citi is seeking a Blockchain Software Developer to join the Digital Assets Platform engineering team. This role focuses on building Web3-native components, on-chain integrations, and scalable backend services for institutional digital finance use cases.

The candidate will work in a globally distributed team, contribute to secure smart contract development, and align with enterprise-grade software standards in a fast-evolving fintech environment.

Qualifications

• Bachelor's degree in Computer Science, Engineering, or related discipline; MS is a plus.
• Extensive software engineering experience with strong backend foundation.
• Proven hands-on Web3 and blockchain application development, including smart contracts and protocol integration.
• Solid experience with Java/Spring and/or Node.js in enterprise environments.
• Proficiency in Solidity and testing frameworks (Hardhat, Foundry, Truffle).
• Hands-on experience with Web3 libraries (Web3J, Web3JS, Ethers.js, Viem).
• Understanding of blockchain fundamentals: consensus, gas models, wallet infrastructure, key management.
• Familiarity with token standards (ERC‑20, ERC‑721, ERC‑1155, ERC‑3525).
• Experience with asynchronous programming, event-driven architectures, and messaging (Kafka, RabbitMQ).
• Familiarity with Docker, Kubernetes, CI/CD, and DevOps practices.

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, Canton, Solana, or equivalent).
• Develop, test, and audit smart contracts written in Solidity or equivalent languages, ensuring security and gas efficiency.
• Integrate Web3 libraries and SDKs into enterprise Java and/or Node.js backend services.
• Implement asynchronous, event-driven architectures to handle on-chain events and transaction lifecycle management.
• Collaborate with architects and senior engineers to design scalable, secure Web3 infrastructure.
• Participate in code reviews, providing technical feedback to maintain high standards.
• Support integration of digital asset custody solutions, tokenization frameworks, and DeFi/TradFi bridging components.
• Contribute to technical documentation, including smart contract specs and architecture notes.
• Stay current with Web3 ecosystem developments and cross-chain interoperability.

Education

Bachelor's degree in Computer Science or related field

Tools

Web3J

Web3JS

Ethers.js

Viem

Java/Spring

Node.js

Docker

Kubernetes

Jira

Jenkins

Hardhat/Foundry/Truffle

Job description

26983955 Blockchain Software Developer - Digital Assets Platform (Open)

Discover your future at Citi

Working at Citi is far more than just a job. A career with us means joining a team of more than 230,000 dedicated people from around the globe. At Citi, you'll have the opportunity to grow your career, give back to your community and make a real impact.

Job Overview

Citi is seeking a passionate and skilled Digital Assets Blockchain Web3 Engineer to join the Citi Integrated Digital Assets Platform (CIDAP) engineering team. This is a hands-on engineering role for a developer who is deeply enthusiastic about the intersection of decentralized technologies and institutional finance.

The successful candidate will contribute to the design, development, and deployment of Web3-native components and integrations that power Citi's digital asset infrastructure — spanning tokenization, smart contracts, on-chain settlement, and blockchain protocol integrations. You will work within a collaborative, globally distributed team of engineers, architects, and business technologists who are building the next generation of institutional digital finance capabilities.

We are looking for someone who brings strong Web3 engineering fundamentals, a curiosity for emerging blockchain ecosystems, and the ability to bridge decentralized technology patterns with enterprise-grade software standards.

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, Canton, Solana, 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/TradFi 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
• 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 (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 blockchain networks (Hyperledger Besu, Solana, Canton) 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
• 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

Development Value

• Work on real-world, production-grade Web3 infrastructure at the scale and complexity of a global systemically important bank
• Gain deep exposure to institutional digital asset use cases — including tokenized securities, digital cash, on-chain settlement, and programmable finance
• Collaborate with world-class engineers, architects, and business leaders who are defining the future of digital finance at Citi
• Build expertise across both Web3-native and enterprise technology stacks, making you a uniquely versatile engineer in a rapidly growing field
• Access continuous learning opportunities, including emerging protocol research, industry conferences, and internal innovation programs
• Contribute to a platform with global reach and real commercial impact, with visibility across Citi's technology and business leadership

Citi is an equal opportunity and affirmative action employer. Qualified applicants will receive consideration without regard to their race, color, religion, sex, sexual orientation, gender identity, national origin, disability, or status as a protected veteran.

This job description provides a high-level review of the types of work performed. Other job-related duties may be assigned as required.

Citi is an equal opportunity employer, and qualified candidates will receive consideration without regard to their race, color, religion, sex, sexual orientation, gender identity, national origin, disability, status as a protected veteran, or any other characteristic protected by law.

If you are a person with a disability and need a reasonable accommodation to use our search tools and/or apply for a career opportunity review Accessibility at Citi.

Alongside these benefits Citi is committed to ensuring our workplace is where everyone feels comfortable coming to work as their whole self, every day. We want the best talent around the world to be energized to join us, motivated to stay and empowered to thrive.