Senior Python Engineer

We’re expanding our engineering team and hiring a Senior Python Software Engineer to help own and develop an established trading-related application. The system runs in production, processes high-frequency real-time data, and needs careful performance engineering and disciplined testing to keep latency and reliability where they should be.

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.

Location: UK-based preferred

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 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 tradeoffs 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

• Experience with trading, market data, or execution systems.
• Familiarity with Interactive Brokers TWS or other brokerage APIs
• 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.