Blockchain Architect

Pyramid Consulting, Inc; New York (NY); On-site; USD 140,000 - 210,000; Full time

Job summary

Citi is seeking a senior Web3 backend engineer to design, develop, and deploy Web3 components for the Digital Asset Platform, including smart contracts, on-chain listeners, wallet integrations, and protocol connectors.

You will work with Java/Spring or Node.js backends, implement event-driven architectures, and ensure security and gas efficiency in smart contracts. Experience with Solidity and Web3 libraries is required.

Qualifications

• Bachelor's degree in Computer Science, Engineering, or related field.
• 8+ years in software engineering with strong backend foundation.
• 2–4 years in Web3 and blockchain app development including smart contracts.
• 3–5 years backend development with Java/Spring or Node.js.
• Proficiency in Solidity and testing frameworks (Hardhat, Foundry, Truffle).
• Hands-on with Web3 libraries: Web3J, Web3JS, Ethers.js, Viem.
• Solid understanding of blockchain basics, token standards, and wallets.
• Experience with permissioned networks (Hyperledger Besu, Fabric, Corda) is a plus.
• Asynchronous programming, event-driven systems, and DevOps familiarity.

Responsibilities

• Design, develop, and deploy Web3 components and integrations for Citi's Digital Asset Platform.
• Build backends interfacing with public and permissioned blockchains (Ethereum, Besu, Corda).
• Develop, test, and audit Solidity contracts for security and efficiency.
• Integrate Web3 libraries into enterprise Java and/or Node.js backends.
• Implement event-driven architectures for on-chain events and lifecycle management.
• Collaborate with architects to design scalable, secure Web3 infrastructure.
• Participate in code reviews to uphold engineering standards.
• Support custody solutions, tokenization frameworks, and DeFi/TradFi bridging.
• Contribute to technical docs including specs and integration guides.
• Stay updated on protocol upgrades, token standards, Layer 2s, and tooling.

Skills

Web3 backend

Solidity

Java/Spring

Node.js

Security best practices

DevOps

Kubernetes

Web3 libraries

Education

Bachelor's degree in Computer Science or related

MS preferred

Tools

Web3J

Web3JS

Ethers.js

Viem

Docker

Kubernetes

Git

Jira

Job description

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
• 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