At a Glance
- Tasks: Build low-latency trading systems using C++ and Python on Linux.
- Company: Award-winning fintech company revolutionising trading technology.
- Benefits: Up to 30 days leave, private health insurance, and remote work flexibility.
- Other info: Opportunities for career growth and embracing AI tools in engineering.
- Why this job: Join a small, expert team and make a real impact in high-performance trading.
- Qualifications: Strong C++ skills and experience with performance-sensitive systems required.
The predicted salary is between 56700 - 69300 £ per year.
Reactive Markets is the 2026 OTC Trading Platform of the Year (Risk.net). Our network handles over $50 billion in daily trading volumes across FX, Equities, and Cryptocurrency, connecting 40+ of the world's leading liquidity providers.
We build trading systems that operate at the edge of what's technically possible — where nanoseconds matter and a dropped message costs real money. Our engineering team is small, senior, and deeply invested in the craft of building cutting-edge, reliable, high-performance systems.
We're looking for a C++ Software Engineer who wants to build low-latency trading infrastructure on Linux. You'll work on the core components of our Switchboard trading platform — pricing engines, connectivity gateways, market-data systems, and the messaging layer that ties them together.
You build it, you test it, you deploy it, you support it in production, and you improve it. Occasional hours outside the normal working day are required for production releases, scheduled maintenance windows, and Level 3 support during critical incidents.
- Modern C++20 and Go on Linux — a modern software stack based on open source
- Cloud-native infrastructure on AWS with colocation in key data centres
- Market-data and reference-data pipelines across multiple asset classes
- Observability and monitoring — dashboards, alerting, and metrics that make system behaviour visible
Requirements:
- Strong C++ with Linux systems programming (3+ years)
- Experience with performance-sensitive systems (profiling, optimisation, deterministic behaviour)
- Familiarity with networking fundamentals (TCP/UDP, socket programming)
- Go experience is a strong bonus — we use Go extensively for microservices and command-line tooling, and you'll be expected to work with it internally. If you don't know it yet, strong C++ engineers pick it up quickly
- Python for scripting, automation, testing, and data analysis — used across the platform for tooling and operational workflows
- Experience in financial services or trading technology is a plus but not essential
- You ship. Clear, proactive communication — especially when things go wrong — is essential
- You care about quality. You embrace AI tooling. We use AI tools (Claude, Gemini) to amplify our engineering capability — from code review and debugging to incident investigation and documentation.
Real problems — trading systems where performance is measured in microseconds, not user clicks.
Competitive package — up to 30 days leave + bank holidays, private health insurance, pension, life insurance, dental/optical cashback, cycle to work, socials and offsites.
Remote-friendly — work from home with flexibility. Growth — career progression to senior roles, performance specialisation, or technical leadership. We believe in transparency, honest feedback, and writing things down. We frame AI as empowering people — removing toil, amplifying capability, enabling higher-value work.
Stage 1: Initial Conversation with Talent Acquisition
- Video call, ~30-45 minutes
- Video call, ~60 minutes
- Video call, interactive session, ~60 minutes
What to expect in each stage will be explained by Talent Acquisition if you're invited to interview. Please apply directly via this job posting — all applications, including those submitted via LinkedIn, are managed through our applicant tracking system, so you'll always land in the same place regardless of where you found this role.
We welcome applications from all qualified candidates regardless of age, disability, gender reassignment, marriage or civil partnership, pregnancy or maternity, race, religion or belief, sex, or sexual orientation.
Data Protection: By applying, you consent to Reactive Markets processing your personal data for recruitment purposes.
Software Engineer - C++/Python (Remote) employer: Reactive Markets
Reactive Markets is an exceptional employer, offering a dynamic remote work environment in the UK that fosters innovation and collaboration. With a strong emphasis on employee growth, you will have the opportunity to mentor fellow engineers while working with cutting-edge technologies in a supportive culture that values your contributions to high-performance trading solutions.
