Senior Blockchain Developer

Project description

Modernization as a Service (MaaS) is a cross-functional practice supporting all business verticals within the company.

We are seeking a Senior Blockchain Developer to join our project with our client, a leading financial institution in the UK.

Responsibilities

• - Design, build, and deploy Web3 components, including smart contracts, event listeners, wallet integrations, and protocol connectors for a digital asset platform.
• Develop backend services using Java/Spring and Node.js to interface with public and permissioned blockchains through SDKs such as Web3J, Ethers.js, and Viem.
• Write, test, and audit Solidity contracts to ensure security, correctness, and gas efficiency.
• Implement event-driven architectures to handle on-chain events, transaction lifecycles, and state synchronization.
• Support tokenization, custody, and DeFi/TradFi bridging integrations, contributing to architectural and design decisions.
• Maintain engineering standards by performing code reviews, producing documentation, and participating in Agile delivery within a distributed global team.

SKILLS

Must have

• Core / must-have:
• Smart contracts: Solidity development, testing (Hardhat, Foundry, Truffle), security best practices, gas efficiency
• Web3 libraries: Web3J, Web3JS, Ethers.js, Viem - integrated into enterprise backends
• Backend engineering: Java/Spring and/or Node.js, API design, microservices, design patterns
• Blockchain fundamentals: consensus mechanisms, transaction lifecycle, gas models, wallet infrastructure, key management
• Token standards: ERC-20, ERC-721, ERC-1155, ERC-3525 and tokenization patterns
• Event-driven / async architecture: on-chain event listeners, state synchronization, message queuing (Kafka, RabbitMQ)
• Cryptography applied to blockchain: digital signatures, hashing, PKI, secure key management
• DevOps: Docker, Kubernetes, Helm, CI/CD (Jenkins), Git, Jira, observability tooling
• Education: BSc in CS/Engineering; extensive overall software engineering experience with proven hands-on Web3 delivery

Soft skills / competencies

• Security mindset (reentrancy, front-running, integer overflow awareness)
• Attention to detail and rigour - driven by the immutability of on-chain deployments
• Curiosity and fast adaptation to a rapidly evolving ecosystem
• Clear communication with engineers, architects, and non-technical stakeholders
• Self-managed delivery within Agile/Scrum sprints, distributed global team collaboration
• Code review participation and technical documentation

Nice to have

• Permissioned/alternative networks: Hyperledger Besu, Canton, Solana

Layer 2 (Polygon, Optimism, zkSync) and cross-chain interoperability

• Digital asset custody, DeFi/TradFi bridging
• Financial services or other regulated-industry background
• MSc