Remote C++ Software Engineer

Remote (UK-based) | Full-Time

Reactive Markets is the 2026 OTC Trading Platform of the Year (). 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.

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.

• 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

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. 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

• Git and shell scripting

• Experience in financial services or trading technology is a plus but not essential

How you work:

• You ship. You're delivery-focused — you iterate, you improve, you get things into production

• You own it. When you build something, you take responsibility for its behaviour in production. You respond to incidents (15-minute acknowledgement SLA during working hours), investigate issues, and close the loop

• You write things down. Documentation is not an afterthought — it's how we scale knowledge across a distributed team. If it's not written down, it doesn't exist

• You communicate. We're a distributed team across multiple time zones. Clear, proactive communication — especially when things go wrong — is essential

• You care about quality. You write clean, testable code. You review your peers' work thoughtfully. You push for continuous improvement without gold-plating

• You embrace AI tooling. We use AI tools (Claude, Gemini) to amplify our engineering capability — from code review and debugging to incident investigation and…