Senior C++ Software Engineer

Senior C++ Software Engineer Remote (UK-based) | Full-Time About Us 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. The Role We're looking for a Senior C++ Software Engineer who can shape the technical direction of our Switchboard trading platform while continuing to write excellent code. You'll work on the most performance-critical components — pricing engines, connectivity gateways, market-data systems, and the messaging layer that ties them together — and you'll have a direct influence on architectural decisions that affect the entire platform. 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. Beyond your own delivery, you'll provide technical oversight across the team — reviewing designs, challenging assumptions, and mentoring engineers who are earlier in their careers. You'll help us maintain the quality bar that our clients depend on, and you'll contribute to the architectural decisions that determine how well our platform scales. 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