Blockchain Web3 Engineer for Digital Asset 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

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.