[Hiring] Senior C++ Software Engineer @Reactive Markets

Role Description

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 it matters.

Qualifications

• Strong C++ with Linux systems programming (5+ years)
• Comfortable working close to the metal — you understand what's underneath your code
• Proven track record of optimising complex, latency-sensitive systems
• Deep understanding of distributed systems architecture and network protocols (TCP/UDP, socket programming, FIX)
• Experience with system design and architectural trade-offs
• Go experience is a strong bonus
• Python for scripting, automation, testing, and data analysis
• Git and shell scripting
• Experience in financial services or trading technology is a plus but not essential

Requirements

• You ship.
• You're delivery-focused — you iterate, you improve, you get things into production.
• You own it.
• You raise the bar.
• You mentor.
• You write things down.
• You communicate.
• You care about quality.
• You embrace AI tooling.

Benefits

• Real problems — trading systems where performance is measured in microseconds, not user clicks.
• Technical influence — direct input into architectural decisions, solution design, and the technical direction of the platform.
• An excellent team — senior engineers who care about craft, collaborate openly, and hold each other to high standards.
• Ownership — small teams, clear accountability, direct impact on the platform and our clients.
• 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. We trust our people to deliver.
• Sustainable pace — we work hard, but we don't burn people out. Balance is how we stay sharp.
• Growth — career progression to lead roles, performance specialisation, or technical leadership.