Senior Software Engineer (Python) - Trading Systems

We’re hiring a Senior Software Engineer (Python) - Trading Systems to own and evolve a production options trading system. It runs during market hours, ingests real-time market data, and requires profiling-led performance engineering to keep p50/p99 latency, jitter, and reliability within tight bounds.

You’ll take meaningful ownership day-to-day, partnering closely with the founder and the engineering team to prioritise work, ship improvements quickly, and keep the system fast, reliable, and correct.

Who this is (and isn’t) for

• This role is for engineers who have built and owned real-time, performance-critical systems.
• It is not suitable for candidates whose experience is mainly web product development (frontend-heavy or CRUD backends).
• We’re looking for proven experience with measuring and improving p99 latency/jitter and operating systems during time-critical windows.

Location: UK-based

Working style: Mostly remote, occasional in-person days for planning/coordination

Support: Availability during core market hours when needed

What You’ll Do

• Own and improve a production Python codebase that runs during market hours.
• Build and optimise real-time market data pipelines (throughput, p50/p99 latency, jitter).
• Do profiling-driven performance work across ingestion → compute → messaging → consumers.
• Improve reliability: freshness/staleness handling, safe degradation, back pressure, fault isolation.
• Strengthen “developer leverage”: replay/simulation tools, regression tests, and debugging tooling.
• Work with cloud infrastructure, deployment, monitoring, and incident response.
• Collaborate directly with the founder and engineering team on architecture and roadmap.

Essential Skills

• 5+ years professional Python experience; you’ve shipped and owned production systems.
• Built/owned a real-time / low-latency system (not batch ETL) with measurable performance goals.
• Strong understanding of async + multiprocessing trade offs and performance profiling.
• Comfortable owning an existing codebase: refactors, tests, architecture improvements.
• Experience with messaging / event-driven systems and strong API/schema discipline.
• Production ownership mindset: incidents, monitoring, and fast debugging when it matters.
• UK-based preferred and able to support core market hours when required.

Desirable Skills

• Interactive Brokers (TWS/IB Gateway) or similar brokerage/execution APIs.
• Experience with trading, market data, or execution systems.
• Experience designing safety constraints/guardrails in automated systems.

What We Offer

• Competitive salary (negotiable) + performance-related bonus.
• Mostly remote, with some in-office collaboration days for coordination and planning
• Lean environment, direct impact on a live system.
• High ownership and influence over system design and roadmap.