Senior Quantitative Developer

Radley James; New York (NY); On-site; USD 225,000 - 325,000; Full time

Job summary

Radley James is seeking a Senior/Principal Quantitative Developer to join a well-capitalized fintech building real-time trading infrastructure in New York. This hands-on role blends quantitative finance with high-performance backend systems, including position-keeping, data pipelines, and low-latency APIs.

You will own production-critical components, implement streaming with Kafka, and collaborate with trading, risk and operations.

Qualifications

• 8+ years in financial markets or demanding fintech environments.
• Strong SQL/PostgreSQL with performance optimization.
• Experience designing production REST APIs (FastAPI or similar).
• Hands-on Kafka or comparable event-streaming experience.
• Experience with Redis or similar caching technologies.
• Excellent testing discipline and a correctness-first mindset.
• Comfortable owning critical production systems.
• Exposure to AWS, distributed databases and infrastructure-as-code.

Responsibilities

• Design and build real-time position-keeping and financial data pipelines.
• Develop stateful event-streaming systems using Kafka and CDC patterns.
• Own APIs serving real-time positions and balances to downstream applications.
• Build and evolve booking models and transaction flows.
• Engineer for financial correctness through reconciliation, replay, gap detection and point-in-time accuracy.
• Take production ownership across performance, observability, incident response and reliability.
• Partner with quantitative, trading, risk and clearing stakeholders.
• Influence architecture and technical direction of the platform.

Skills

SQL/PostgreSQL

REST APIs

Kafka

Redis

Testing discipline

Production systems ownership

Financial markets experience

Tools

AWS

Terraform

Distributed databases

Job description

Senior / Principal Quantitative Developer – Real-Time Trading Systems

Location: New York, NY

Base salary: Up to $325,000 + performance bonus + benefits

I’m working with a well-capitalized financial technology business looking to hire a Senior/Principal Quantitative Developer into a team responsible for mission-critical, real-time financial infrastructure.

This is a hands-on engineering role focused on building highly reliable systems responsible for positions, balances and P&L across a sophisticated trading environment. The platform is consumed by trading, risk, clearing and reporting functions, meaning accuracy, availability and performance are critical.

What you’ll be doing:

• Design and build real-time position-keeping and financial data pipelines
• Develop stateful event-streaming systems using Kafka and CDC patterns
• Own APIs serving real-time positions and balances to downstream applications
• Build and evolve booking models and transaction flows
• Engineer for financial correctness through reconciliation, replay, gap detection and point-in-time accuracy
• Take significant production ownership across performance, observability, incident response and reliability
• Partner closely with quantitative, trading, risk and clearing stakeholders
• Have increasing influence over the architecture and technical direction of the platform

What we’re looking for:

• Deep SQL/PostgreSQL knowledge, including schema design and performance optimization
• Experience designing production REST APIs, ideally with FastAPI or similar
• Hands-on Kafka or comparable event-streaming experience
• Experience with Redis or similar caching technologies
• Excellent testing discipline and a correctness-first engineering mindset
• Comfortable owning critical production systems
• Ideally 8+ years within financial markets or similarly demanding financial technology environments

Experience building position-keeping, ledger, books-and-records or P&L systems would be particularly valuable. Exposure to AWS, distributed databases and infrastructure-as-code is also advantageous.

This would suit a senior engineer who enjoys combining quantitative finance with high-performance backend and distributed-systems engineering, while taking genuine ownership of business-critical infrastructure.

Base: $225,000–$325,000 + performance bonus + benefits.