Senior Python Developer - Up to £180,000 P/A + Bonus - London

Job Title: Senior Software Developer (python)

Client: Stealth Prop Trading firm (HFT)

Experience Level: 5+ years

Salary: Up to £180k + Bonus + Package

Location: London (Hybrid)

About the Client

Some firms build software.

Others build technology that competes directly with the world's fastest markets.

Our client is a highly successful, technology-first proprietary trading firm operating firmly under the radar. With no external investors, no clients to service, and no unnecessary layers of bureaucracy, every engineering decision is driven by one question: does it make us faster, smarter, or more competitive?

Trading across global markets, they develop ultra-low latency systems, sophisticated quantitative infrastructure, and high-performance trading platforms that process enormous volumes of market data in real time.

Engineering sits at the centre of everything they do. Developers work shoulder-to-shoulder with traders and quantitative researchers, solving some of the most technically demanding problems in finance while enjoying the freedom to experiment, innovate, and continually push technological boundaries.

If you're passionate about building exceptional software and want to work somewhere where engineering excellence genuinely matters, this is the kind of opportunity that rarely reaches the open market.

The Role

You'll be building the software that powers a modern high-frequency trading business, working across both front and middle office systems. From real-time trading infrastructure and market data services to risk platforms, analytics, and operational tooling, you'll have the opportunity to contribute across the entire trading lifecycle.

You'll work directly alongside traders, quantitative researchers, and experienced software engineers to build highly performant, production-critical systems where latency, scalability, and reliability genuinely matter.

There are no rigid team boundaries or endless approval chains—just talented engineers solving challenging problems together.

If you enjoy ownership, variety, and writing software that has an immediate and measurable impact, you'll feel right at home.

Key Responsibilities

• Design, develop, and maintain production-grade Python applications supporting high-frequency trading operations.
• Build scalable services for market data processing, trading workflows, and middle-office infrastructure.
• Collaborate closely with traders and quantitative researchers to transform ideas into robust production systems.
• Optimise applications for performance, scalability, and reliability in demanding production environments.
• Develop APIs, internal tooling, and automation that improve the efficiency of the wider engineering organisation.
• Build resilient distributed systems capable of handling high-throughput financial data.
• Improve observability through monitoring, logging, testing, and automated deployment.
• Contribute to architectural decisions while continually raising engineering standards across the business.

Required Skills & Experience

• 4 + years of commercial Python development experience.
• Previous experience working within capital markets, electronic trading, investment banking, hedge funds, market makers, exchanges, or proprietary trading firms.
• Strong software engineering fundamentals with a passion for writing clean, maintainable code.
• Experience building scalable backend systems or distributed applications.
• Excellent understanding of data structures, concurrency, and performance optimisation.
• Comfortable working on Linux-based production environments.
• Experience working with relational databases and writing efficient SQL.
• An inquisitive mindset and genuine enthusiasm for solving technically challenging problems.
• Strong Academic background - Degree from a top world institution

Nice to Have

• Experience working with trading systems, order management, or market data platforms.
• Knowledge of financial markets, market microstructure, or electronic execution.
• Experience with messaging technologies such as Kafka or RabbitMQ.
• Familiarity with Docker, Kubernetes, and modern cloud platforms.
• Exposure to asynchronous Python, multiprocessing, or high-performance computing.
• Experience with C++, Rust, or another systems programming language.
• Understanding of risk systems, pricing, or quantitative research infrastructure.