Senior Python Engineer - Real-Time Trading Systems (UK Only)

We’re hiring a Senior Python Engineer to take ownership of a live, production trading system used in options markets.

This is a hands-on engineering role focused on real-time systems, production reliability, performance profiling, and safe operation during live market hours.

This is not a general backend or web-product role. We are not looking for engineers whose background is mainly CRUD applications, internal business systems, or frontend-heavy product development.

We want engineers who have already built, operated, and improved performance-critical, real-time production systems.

Location: UK only

Applicants must already be based in the UK and must have the legal right to work in the UK. We are not considering overseas applicants or relocation cases for this role.

Working style: Mostly remote, with occasional in-person days in the UK for planning and coordination

Support expectations: Availability during core US market hours is required

What You'll Do

• Own and improve a production Python trading system that runs during market hours
• Build new capabilities across a high-impact roadmap that includes feature expansion, algorithmic improvement, and integration of new components
• Help bring new ideas into production, from early implementation through to safe rollout and operational support
• Optimise performance and reliability in parts of the system where timing, stability, and correctness matter
• Improve the quality of the engineering environment through better tooling, test coverage, replay/debug workflows, and observability
• Make the platform more robust under real-world conditions, including degraded inputs, operational faults, and time-critical scenarios
• Work directly with the founder and engineering team in a high-ownership environment where good decisions turn into shipped changes quickly
• Have visible influence over both day-to-day engineering priorities and the longer-term direction of the platform

Who This Role Is For

This role is for engineers who have:

• built or owned real-time, event-driven, or latency-sensitive systems in production
• worked on systems where p50/p99 latency, jitter, throughput, or correctness mattered
• supported systems during time-critical operating windows
• improved existing codebases through careful refactoring, testing, instrumentation, and operational hardening

Who This Role Is Not For

This role is unlikely to be a fit if your experience is mainly:

• web application development
• standard SaaS backend work
• REST API / CRUD application development
• frontend-heavy product engineering
• batch ETL or offline data processing without real-time operational ownership

Essential Requirements

• UK-based only and already have the legal right to work in the UK
• 5+ years of professional software engineering experience
• Strong production Python experience
• Experience owning or materially improving a real-time, event-driven, or low-latency production system
• Experience measuring and improving performance using profiling, instrumentation, and production diagnostics
• Strong understanding of concurrency trade-offs in Python, including async, multiprocessing, and process boundaries
• Experience working in existing codebases and improving them through refactoring, testing, and better architecture
• Experience with messaging/event-driven systems and disciplined data contracts or schemas
• Strong production ownership mindset: monitoring, debugging, incidents, and reliability under pressure

Preferred Experience

• Experience with trading systems, market data systems, or execution infrastructure
• Experience with brokerage or execution APIs such as Interactive Brokers
• Experience designing safety guardrails or operational constraints in automated systems
• Experience with replay, simulation, or deterministic regression tooling for live systems
• Experience with Linux production environments, observability, and performance troubleshooting

What We Offer

• Competitive salary, negotiable based on experience
• Performance-related bonus
• Mostly remote working, with occasional in-person collaboration days in the UK
• High ownership in a lean team
• Direct influence over a live production system and future technical roadmap