Blockchain Developer

TalentOla; New York (NY); On-site; USD 105,000 - 135,000; Full time

Job summary

Citi Bank is seeking a Senior Blockchain Developer to design, develop, and deploy Web3 components for its Digital Asset Platform. You will work with smart contracts, on-chain event listeners, and wallet integrations across Ethereum, Hyperledger Besu, Corda, and other networks.

Strong backend experience (Java/Spring or Node.js) and a solid understanding of token standards and blockchain fundamentals are required. Join a distributed global team following Agile/Scrum practices.

Qualifications

• Bachelor's degree in Computer Science, Engineering, or related field (MS a plus).
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Responsibilities

• Design, develop, and deploy Web3 components and integrations for Citi's Digital Asset Platform.
• 2 to 4 years hands-on Web3 and blockchain development.

Skills

Web3 development depth

Backend engineering fundamentals

Security mindset

Curiosity and adaptability

Collaborative spirit

Delivery orientation

Attention to detail

Tooling proficiency

Education

Bachelor's degree in Computer Science, Engineering, or related; MS a plus

8+ years total software engineering experience

2-4 years Web3/blockchain app development

3-5 years backend with Java/Spring or Node.js

Tools

Web3J

Web3JS

Ethers.js

Viem

Hardhat

Foundry

Truffle

Docker

Kubernetes

Git

Jira

CI/CD tooling

Job description

Job Description

Role: Blockchain Developer

Location: 388 Greenwich Street, New York, NY 10013 / 480 Washington Boulevard, Jersey City, NJ 07310

Position Type: Fulltime

Client- Citi Bank

Salary range- 120K

7+ Years of exp

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, Corda, 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
• 8+ years of overall software engineering experience, with a strong backend development foundation
• 2 to 4 years of hands-on experience in Web3 and blockchain application development, including smart contract development and blockchain protocol integration
• 3 to 5 years of 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 permissioned blockchain networks (Hyperledger Besu, Fabric, Corda, or R3) 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