Blockchain Software Developer - Digital Assets Platform

Citigroup Inc.; Greater London; On-site; GBP 90,000 - 130,000; Full time

Benefits offered by this job

27 days annual leave

Discretional annual bonus

Private Medical Care & Life Insurance

Employee Assistance Program

Pension Plan

Paid Parental Leave

Special discounts for employees

Job summary

Citigroup Inc. in London is seeking a Digital Assets Blockchain Web3 Engineer to join the CIDAP team. You will design, build, and deploy Web3-native components and integrations powering Citi's digital asset infrastructure, spanning tokenization, on-chain settlement, and protocol connectors.

You will work with Java/Spring or Node.js backends, integrate Web3 libraries, and contribute to secure, scalable enterprise-grade Web3 solutions within an Agile, globally distributed team.

Qualifications

• Bachelor's degree in CS/Engineering or related field.
• Extensive software engineering with a backend focus.
• Hands-on Web3 and blockchain app development incl. smart contracts.
• Solid backend experience with Java/Spring or Node.js.
• Proficiency in Solidity and testing/security practices.
• Experience with Web3 libraries (Web3J, Web3JS, Ethers.js, Viem).
• Knowledge of blockchain fundamentals and token standards.
• Familiarity with Agile/Scrum and distributed teams.

Responsibilities

• Design, develop, and deploy Web3 components and integrations for CIDAP.
• Build and maintain backend services interfacing with public/permitted blockchains.
• Develop, test, and audit Solidity smart contracts for security and efficiency.
• Integrate Web3 libraries into enterprise Java/Node.js backends.
• Implement asynchronous, event-driven architectures for on-chain events.
• Collaborate with architects to design scalable, secure Web3 infra.
• Participate in code reviews and contribute to technical docs.
• Support custody, tokenization, and DeFi/TradFi bridging integrations.
• Stay current with Web3 ecosystem and emerging tooling.

Skills

Web3 Engineering

Backend Eng

Java/Spring

Node.js

Solidity

Security Best Practices

Cryptography Basics

Education

Bachelor's degree in CS/Engineering

Tools

Web3J

Web3JS

Ethers.js

Viem

Hardhat

Foundry

Truffle

Docker

Kubernetes

Git

Jira

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

As a Blockchain Software Developer at Citi, you will be at the forefront of one of the most exciting and strategically significant technology domains in institutional finance. You will:

• 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.

What we’ll provide you

By joining Citi London, you will not only be part of a business casual workplace with a hybrid working model (up to 2 days working at home per week), but also receive a competitive base salary (which is annually reviewed), and enjoy a whole host of additional benefits such as:

• 27 days annual leave (plus bank holidays)
• A discretional annual performance related bonus
• Private Medical Care & Life Insurance
• Employee Assistance Program
• Pension Plan
• Paid Parental Leave
• Special discounts for employees, family, and friends
• Access to an array of learning and development resources

Visit ourGlobal Benefitspage to learn more.

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.

#LI-AP2

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Job Family Group:

Technology

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Job Family:

Applications Development

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Time Type:

Full time

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Most Relevant Skills

Please see the requirements listed above.

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Other Relevant Skills

For complementary skills, please see above and/or contact the recruiter.

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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.

View Citi's EEO Policy Statement and the Know Your Rights poster.