Blockchain Software Developer – Digital Assets Platform

Overview

In this role you will build and maintain Web3-native components for Citi’s Digital Asset Platform, enabling tokenization, on-chain settlement, and institutional blockchain integrations. You will join a global, collaborative team to design scalable, secure Web3 infrastructure that bridges decentralized tech with enterprise-grade standards. You’ll work across smart contracts, backend services, and tooling to support delivery and security at scale. This is an opportunity to shape institutional digital finance capabilities and stay at the forefront of the Web3 ecosystem. You will engage in hands-on development, code reviews, and cross-team collaboration to drive real-world impact.

Pay / Benefits

• 27 days annual leave (plus bank holidays)
• discretionary annual bonus
• Private Medical Care & Life Insurance
• Pension Plan
• Paid Parental Leave
• Learning and development resources

Responsibilities

• Design, develop, and deploy Web3 components and integrations (smart contracts, on-chain event listeners, wallet integrations, protocol connectors)
• Build and maintain backend services interfacing with public and permissioned blockchains (Ethereum, Hyperledger Besu, Canton, Solana)
• Develop, test, and audit Solidity smart contracts focusing on security and gas efficiency
• Integrate Web3 libraries into enterprise Java and/or Node.js backends (Web3J, Web3JS, Ethers.js, Viem)
• Implement asynchronous, event-driven architectures for on-chain events and state synchronization
• Collaborate with architects and senior engineers on scalable, secure Web3 infrastructure
• Participate in code reviews to uphold engineering standards
• Support integration of custody solutions, tokenization frameworks, and DeFi/TradFi bridging components
• Contribute to technical documentation (smart contracts, integration guides, architecture notes)
• Stay updated on Web3 ecosystem developments and relevant tooling
• Work within Agile/Scrum, participating in sprints within a distributed team
• Identify and resolve Web3 stack issues, escalating to meet delivery timelines

Key requirements

• Bachelor’s degree in Computer Science, Engineering, or related discipline
• Extensive software engineering experience with strong backend foundation
• Hands-on Web3 and blockchain application development including smart contracts and protocol integration
• Proficiency in Java/Spring or Node.js backend development
• Solidity development with testing (Hardhat, Foundry, Truffle) and security best practices
• Hands-on experience with Web3 libraries (Web3J, Web3JS, Ethers.js, Viem)
• Solid understanding of blockchain fundamentals (consensus, gas, wallets, key management)
• Experience with token standards (ERC-20, ERC-721, ERC-1155, ERC-3525) and tokenization
• Familiarity with networks (Hyperledger Besu, Solana, Canton) is a strong plus
• Experience with asynchronous programming, event-driven systems, and message queues (Kafka, RabbitMQ)
• Familiarity with DevOps, Docker, Kubernetes, and CI/CD
• Understanding of cryptography, digital signatures, hashing, PKI, and secure key management
• Exposure to Layer 2 solutions and cross-chain interoperability is a plus
• Experience in financial services or regulated environments is a plus
• Familiarity with Agile/Scrum and distributed team collaboration tools

• Collaborative spirit
• Curiosity and adaptability
• Delivery orientation
• Java/Spring backend development
• Node.js backend development
• Solidity smart contracts

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