At a Glance
- Tasks: Develop low-latency trading systems using modern C++ and optimise performance.
- Company: Join Reactive Markets, the award-winning OTC Trading Platform of the Year.
- Benefits: Enjoy up to 30 days leave, private health insurance, and a flexible remote-friendly environment.
- Other info: Opportunity for career progression and involvement in cutting-edge projects.
- Why this job: Make a real impact in high-performance trading technology with a small, senior team.
- Qualifications: 3+ years of C++ experience on Linux and familiarity with networking fundamentals.
The predicted salary is between 56700 - 69300 £ per year.
Write the C++ behind a trading network that handles billions in daily volume, and grow quickly alongside a small, senior team. You will work on pricing engines, connectivity gateways, market data and the messaging layer that ties them together, then own what you ship in production.
About Us
Reactive Markets is the 2026 OTC Trading Platform of the Year (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 are looking for a C++ Software Engineer who wants to build low-latency trading infrastructure on Linux. You will work on the core components of our Switchboard trading platform, alongside senior engineers who review your work and help you grow. You build it, test it, deploy it, support it in production and improve it. Occasional hours outside the normal working day are needed for production releases, scheduled maintenance windows and Level 3 support during critical incidents. We keep this to a minimum and recognise the commitment.
What You'll Work On
- Modern C++20 on Linux, with Go for microservices and tooling
- 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
- Cloud-native infrastructure on AWS, with colocation in key data centres
- Observability: dashboards, alerting and metrics that make system behaviour visible
What We Need
- 3+ years of strong C++ with Linux systems programming, working close to the metal
- Experience with performance-sensitive systems: profiling, optimisation and deterministic behaviour
- Familiarity with networking fundamentals (TCP/UDP, sockets)
- Python for scripting, testing and tooling; Git and shell
- Nice to have: Go (strong C++ engineers pick it up quickly), and experience in financial services or trading technology
How You Work
- You ship. You iterate, improve and get things into production.
- You own it. You take responsibility for what you build in production, including incident response (15-minute acknowledgement during working hours).
- You care about quality. Clean, testable code and thoughtful peer reviews, without gold-plating.
- You write things down. We are distributed across time zones; if it is not written down, it does not exist.
- You communicate. Clear, proactive communication, especially when things go wrong.
- You use AI tooling. We use Claude and Gemini for code review, debugging, incident investigation and documentation. Curiosity matters more than expertise.
What You Get
- Real problems: performance measured in microseconds, not user clicks
- A small team of senior engineers with clear accountability and direct impact on clients
- Up to 30 days leave plus bank holidays, private health insurance, pension, life insurance, dental/optical cashback, cycle to work, socials and offsites
- Remote-friendly with real flexibility, and a sustainable pace
- Career progression to senior roles, performance specialisation or technical leadership
Our Hiring Process
- Initial conversation with Talent Acquisition (video, 30-45 min)
- Technical interview with two members of the engineering team (video, ~60 min)
Stages 2 and 3 may swap depending on availability. We aim to keep momentum, and feedback typically comes within a few business days.
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.
Data Protection: By applying, you consent to Reactive Markets processing your personal data for recruitment purposes, in line with our privacy policy.
Software Engineer employer: Reactive Markets
Reactive Markets is an exceptional employer that fosters a dynamic work culture, prioritising innovation and collaboration. With a strong emphasis on employee growth, you will have access to continuous learning opportunities while working closely with a senior engineering team in a hybrid London setting. The company's commitment to outstanding client service and automation ensures that you will be part of a forward-thinking environment that values your contributions.
StudySmarter Expert Advice🤫
We think this is how you could land Software Engineer
✨Join Local Tech Meetups
Get out there and mingle with fellow developers by joining local tech meetups. It’s a fantastic way to meet people who might be working at Reactive Markets or know someone who does. Plus, you can pick up some trendy tech skills and trends while you're at it!
✨Contribute to Open Source Projects
Show off your coding chops by jumping into open-source projects. Not only does this give you practical experience, but it also gets you noticed in the dev community. You'll create a killer portfolio that speaks volumes about your skills to Reactive Markets.
✨Tap into Online Developer Communities
Don’t underestimate the power of online developer communities like GitHub, Stack Overflow, and even Reddit. Participate in discussions, share your projects, and build your visibility. We can often find opportunities through these channels that can lead to a full-time gig at companies like Reactive Markets.
✨Explore Job Boards Specifically for Tech Roles
Keep your eyes peeled on job boards that focus on tech roles. Sites like TechCareers or Stack Overflow Jobs can often have listings for companies like Reactive Markets that might not show up on broader job sites. Make it a habit to check these regularly, and don’t hesitate to apply directly through our website!
We think you need these skills to ace Software Engineer
Some tips for your application 🫡
Show off your coding skills:When applying for a software engineering role, it's super important to showcase your coding skills. Make sure your CV includes your tech stack, any relevant programming languages you’re comfortable with, and examples of projects you've worked on. If you have a GitHub profile, link it up! We love to see code in action.
Tailor your portfolio:For a full-time role, we’d expect to see some solid examples of your work in your portfolio. Make sure to include at least two or three projects that highlight your problem-solving skills and your ability to work with different technologies. Focus on the projects that are most relevant to the position at Reactive Markets.
Craft a killer cover letter:Your cover letter is your chance to stand out—make it personal! Explain why you want to work at Reactive Markets and how your skills align with the role. Show us your passion for software development. We dig enthusiastic candidates who understand the value of collaboration and continuous learning!
Be clear and concise:When it comes to writing your CV and cover letter, clarity is key. Avoid jargon that could confuse us and stick to simple, direct language. Highlight your achievements with quantifiable results where possible, and keep everything easy to read. A well-organised application goes a long way!
How to prepare for a job interview at Reactive Markets
✨Brush Up on Your Coding Skills
For a full-time software engineering role, it's crucial that we stay sharp with our coding abilities. Expect technical questions that might involve solving problems on the spot or discussing algorithms. Practise on platforms like LeetCode or HackerRank to get comfortable with the types of questions that often come up.
✨Know Your Tools and Frameworks
Make sure we’re well-acquainted with the tools and technologies listed in the job description. Familiarise ourselves with any specific frameworks or programming languages mentioned. If Reactive Markets uses React or Node.js, for instance, be ready to discuss how we’ve used them in previous projects or coursework.
✨Showcase Your Projects
Bring along a portfolio that highlights our best work. This could be code samples, GitHub repositories, or any side projects we’ve built. Make sure we can talk through our thought process for each project, especially the challenges we faced and how we solved them—this shows our problem-solving skills in action.
✨Prepare for Behavioural Questions
While technical skills are key, full-time positions also require cultural fit. Be ready to discuss our previous experiences and how we handle teamwork, conflict, and deadlines. Brush up on the STAR method—Situation, Task, Action, Result—to clearly articulate our past experiences when discussing how we've contributed to a team.
