Senior C++ Software Engineer

Senior C++ Software Engineer Remote (UK) | Full-Time Build Trading Systems Where Microseconds Matter Shape the future of electronic trading at Reactive Markets, the 2026 OTC Trading Platform of the Year (Risk.net). Our platform handles $50+ billion in daily trading volume across FX, Equities and Crypto, connecting more than 40 of the world's leading liquidity providers. Every day, our technology powers mission-critical trading infrastructure where reliability, scalability and performance directly impact financial markets. We're looking for an experienced Senior C++ Software Engineer to join our engineering team and help build systems operating at the limits of performance. This is an opportunity to work on complex distributed systems, ultra-low latency architecture and high-throughput messaging platforms while influencing the technical direction of a rapidly growing business. If you're passionate about modern C++, Linux, distributed systems and solving hard engineering problems, we'd love to hear from you. Why Join Reactive Markets? Work on systems processing $50bn+ daily trading volumeInfluence architecture and technical directionModern stack: C++20, Go, Linux, AWSFully remote UK opportunitySmall, senior engineering team with high autonomyDirect ownership from design through productionCompetitive package with comprehensive benefits The Opportunity As a Senior C++ Engineer, you'll play a key role in evolving our award-winning Switchboard trading platform. You'll design, build and optimise performance-critical systems including: Pricing and execution enginesMarket data and reference data platformsConnectivity gateways and FIX integrationsHigh-performance messaging infrastructureLow-latency distributed systemsCloud-native services running on AWS This is a true ownership role. You'll be involved throughout the entire software lifecycle, from architectural design and implementation through to deployment, observability and production support. Alongside hands-on engineering, you'll help shape technical strategy, mentor teammates and contribute to the standards that underpin a world-class trading platform. What You'll Be Working With Modern C++20GoLinux systems programmingAWS cloud infrastructurePythonGit & Shell ScriptingFIX ProtocolTCP/UDP NetworkingDistributed Systems Architecture Engineering Challenges Microsecond-level latency optimisationHigh-throughput messaging systemsLarge-scale market data processingReal-time trading infrastructureSystem observability and resilienceMulti-asset trading workflows What We're Looking For Essential: 5+ years of commercial C++ development experienceStrong Linux systems programming backgroundExperience building high-performance or latency-sensitive applicationsDeep understanding of networking and distributed systemsStrong software design and architectural skillsExperience owning production systems Nice to Have: Go development experienceFinancial markets or trading technology experienceFIX protocol knowledgeAWS cloud experience How You Work We're looking for engineers who: Take ownership of what they buildDeliver high-quality code into productionThrive in challenging technical environmentsMentor and support othersCommunicate clearly in a distributed teamEnjoy solving complex engineering problemsContinuously improve systems, processes and people around them What You'll Get Competitive Benefits Package: 30 days annual leave + bank holidaysPrivate medical insurancePension schemeLife assuranceDental and optical cashbackCycle to Work schemeTeam socials and company off-sites Career Growth: Progression to lead roles, performance specialisation, or technical leadership. We invest in people who invest in usExposure to cutting-edge trading technology.High levels of ownership and autonomyOpportunity to influence a platform used by some of the world's largest financial institutions Remote-First Culture We trust great engineers to do their best work wherever they are. Our remote-first approach prioritises flexibility, collaboration and sustainable working practices without sacrificing technical excellence. Ready to Build at the Edge of What's Possible? Join an award-winning engineering team solving some of the most demanding challenges in electronic trading. Right to Work: Candidates must have the existing right to work in the UK. We are not currently able to offer visa sponsorship for this role. Equal Opportunities: Reactive Markets is an equal opportunities employer. 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. Reasonable Adjustments: If you need any adjustments or support during the application or interview process, please let us know — we're happy to accommodate. Data Protection: By applying, you consent to Reactive Markets processing your personal data for recruitment purposes, in line with our privacy policy. Apply now and help shape the next generation of high-performance trading infrastructure. #CPlusPlus #SoftwareEngineering #TradingTechnology #LowLatency #DistributedSystems #AWS #RemoteJobs #Hiring #TechJobs #EngineeringCareers