We are looking for an experienced Senior Python Software Engineer to take ownership of an established trading-related application and drive its ongoing development. You will manage and enhance the existing codebase, deliver new features, ensure reliability and performance, and help evolve the system as the business grows. This is an excellent opportunity for someone who enjoys autonomy, technical responsibility, and working on low-latency, high-performance applications. What Youll Do Maintain, extend, and optimise an existing Python-based trading application Add new features and improve current capabilities with a focus on performance, reliability and clean architecture Build and optimise real-time pipelines handling high-frequency data Improve latency, throughput, and reliability using profiling and performance engineering Work with Redis, Azure VMs, and Anaconda environments Implement and maintain systems requiring millisecond-level timing precision Troubleshoot production issues quickly during key market hours Collaborate directly with the founder to shape technical direction and priorities Integrate with market data feeds and brokerage/order-routing components Essential Skills Expert-level Python developer (min. 5 years professional python experience) Demonstrable experience with low-latency/high-throughput systems (e.g., real-time data processing, trading/market data, telemetry, adtech bidding, streaming systems, etc.) Strong understanding of asynchronous programming, multiprocessing, and performance optimisation Experience handling large volumes of fast-moving data with careful performance considerations Ability to profile, measure, and improve performance Comfortable owning an existing codebase: refactors, architecture improvements, clean tests Experience with Redis and general database performance considerations Competent with Azure cloud environments (VMs, deployment, monitoring, etc.) Comfortable working independently, making architectural decisions, and maintaining high code quality Strong engineering discipline: correctness, edge cases, careful time-handling, attention to detail UK-based and available for support during core market hours when needed Desirable Skills Experience with algorithmic trading or market data systems Familiarity with Interactive Brokers TWS or other brokerage APIs Experience with distributed systems, message queues, or event-driven architectures Background in financial markets or fintech What We Offer Competitive salary - negotiable based on experience Mostly remote, with some in-office collaboration days for coordination and planning Yearly bonus based on company performance The chance to take significant ownership of a live, production-grade system Long-term role with the opportunity to influence the roadmap and system design A lean environment with minimal bureaucracy and direct impact