UK remote
C++ Software Engineer
About this role
C++ SOFTWARE ENGINEER Remote (UK-based) | Full-Time ABOUT US Reactive Markets is the 2026 OTC Trading Platform of the Year (Risk.net http://Risk.net). Our network handles over $75 billion in daily trading volumes across FX, Equities, and Cryptocurrency, connecting 60+ 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. THE ROLE 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.
This is not a role where you write code and throw it over a wall. You build it, you test it, you deploy it, you support it in production, and you improve it. Our engineers own the full lifecycle — from design through to operational excellence. When something breaks at 4pm on a Friday, you're part of the team that investigates and fixes it. Occasional hours outside the normal working day are required for production releases, scheduled maintenance windows, and Level 3 support during critical incidents.
We keep this to a minimum and recognise the commitment — but owning a production trading platform means being there when it matters. WHAT YOU'LL WORK ON - 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 - Microsecond-level latency optimisation and high-throughput messaging - Market-data and reference-data pipelines across multiple asset classes - FIX protocol integrations with global banks and liquidity providers - Observability and monitoring — dashboards, alerting, and metrics that make system behaviour visible - Production systems that handle real money — reliability is not optional WHAT WE NEED Technical: - Strong C++ with Linux systems programming (3+ years) - Comfortable working close to the metal — you understand what's underneath your code - 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.