Lead Back End Engineer - Contract

• This position is open to U.S.-based candidates only, applications from other regions will not be considered.

• Contract Duration: Initial 2–3 month contract with the potential for long-term extension or full-time conversion based on performance and company fit.

Our client is building a blockchain-based payment system designed to enable real-time, 24/7 movement of digital money across traditional finance and digital asset ecosystems. As a pre-launch startup, they’re developing a new category of financial infrastructure that brings cash on-chain through tokenization while powering the full spectrum of payments for banks, digital asset exchanges, and their customers.

We’re seeking a Lead Backend Engineer to architect and develop the off-chain infrastructure powering this next-generation blockchain-based payment network. You’ll create high-performance TypeScript/Node.js services that bridge smart contracts with traditional banking systems, handle real-time transaction processing, and enable seamless integrations for financial institutions and end users.

About the Role

Reporting directly to the Chief Technology Officer, you’ll own the design and implementation of the backend services architecture. You’ll build scalable Node.js microservices that interface with both smart contract layers and external financial systems. This includes leveraging AI-driven development tools and modern cloud-native patterns to construct real-time event systems, API gateways, and integration layers capable of processing billions in transaction volume. You’ll collaborate closely with the smart contract team to ensure seamless coordination between on-chain and off-chain systems.

What You’ll Do

• Contribute to an AI-first engineering team, utilizing tools like Claude, Linear, and various MCP/AI integrations daily.

• Design and build distributed backend architecture from scratch — implementing TypeScript/Node.js microservices for payment processing, transaction monitoring, and orchestration.

• Implement real-time systems using WebSockets for live transaction updates and webhook infrastructure for third-party integrations.

• Develop and maintain mock banking integration APIs and abstraction layers that connect with payment networks, core banking systems, and regulatory reporting tools.

• Design event-driven architectures for blockchain event processing, reconciliation, and settlement finalization.

• Implement monitoring and observability systems across on-chain and off-chain components.

• Build secure API gateways with OAuth 2.0/FAPI, rate limiting, and detailed audit logging.

• Own technical decisions related to service architecture, database design, messaging patterns, and cloud infrastructure.

Qualifications

• 8+ years of experience in backend engineering, with deep expertise in Node.js/TypeScript and distributed systems.

• Proven track record in building high-throughput financial or payment systems.

• Strong proficiency in WebSocket, webhook, and real-time event processing implementations.

• Experience with AI-driven development tools (e.g., GitHub Copilot, Cursor, Claude).

• Hands-on experience with AWS, GCP, or Azure, and containerization using Docker/Kubernetes.

• Familiarity with blockchain integration patterns, Web3 libraries, and event monitoring.

• Experience with Kafka, RabbitMQ, Redis, and PostgreSQL.

• Understanding of financial protocols and payment systems (or eagerness to learn).

• Proven ability to build systems that scale to millions of users or billions of transactions.

• Knowledge of security best practices, PCI compliance, and financial regulatory requirements.

• Comfortable working independently as a domain expert while collaborating across teams.