At a Glance
- Tasks: Lead FIX client onboarding and provide top-notch technical support across FX and equities.
- Company: Join Reactive Markets, the award-winning OTC Trading Platform of the Year.
- Benefits: Enjoy competitive pay, generous leave, private health insurance, and exciting team socials.
- Other info: Work in a small, senior team with great growth opportunities across multiple asset classes.
- Why this job: Make a real impact by connecting clients to cutting-edge trading technology.
- Qualifications: 3+ years in client onboarding or technical support with strong FIX protocol knowledge.
The predicted salary is between 56700 - 69300 £ per year.
About Us
Reactive Markets is the 2026 OTC Trading Platform of the Year (Risk.net). Our network handles billions in daily trading volumes across FX, Equities, and Cryptocurrency, connecting 35+ 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 reliable, high-performance systems.
The Role
We are seeking a motivated and technically skilled Onboarding and Client Services professional to join our London team. This role will focus on FIX client onboarding, integrations, and client service delivery across FX, equities and digital assets. The successful candidate will work closely with clients and internal teams to ensure seamless connectivity, smooth integration, and exceptional service throughout the client lifecycle.
What You’ll Work On
- FIX Onboarding & Integrations
- Lead and manage FIX client onboarding projects — from initial requirements gathering through certification and production go-live.
- Configure, test, and validate FIX sessions, including order routing, execution reporting, and market data flows.
- Coordinate conformance testing and certification with clients to ensure compliance with platform standards.
- Document onboarding procedures, client configurations, and integration best practices.
- Leverage internal AI and automation tools to streamline client onboarding and troubleshooting.
- Collaborate with engineering and product teams to support new FIX workflows, APIs, and client integration initiatives.
- Client Services
- Serve as a frontline technical support for clients in EMEA across FX and equities business lines.
- Build and maintain strong client relationships, ensuring timely and transparent communication addressing their needs and queries with professionalism and efficiency.
- Provide ongoing technical and operational support for production trading environments.
- Manage client inquiries, troubleshoot workflow or configuration issues, and coordinate resolutions across internal teams.
- Partner with account management, sales and product teams to ensure a positive client experience and successful delivery of platform enhancements.
What We Need
- 3+ years of experience in a client onboarding, integration, or technical support role within a financial technology, trading, or brokerage environment.
- Strong working knowledge of the FIX protocol — message structures, session management, and common trading workflows.
- Proven experience troubleshooting FIX connectivity, analysing logs, and resolving integration issues.
- Familiarity with FX and Equities trading environments, order lifecycle management, and market data connectivity.
- Comfortable with (or curious about) automation and AI-assisted tooling in an operational context.
- Excellent communication and organisational skills, with strong attention to detail and the ability to manage multiple onboarding/client projects in parallel.
Nice-to-have:
- Experience with OMS/EMS platforms, liquidity aggregators, or trading system integrations.
- Exposure to other API protocols and architectures (REST, WebSocket).
- Scripting or automation experience (e.g. Python) and familiarity with monitoring tools (Splunk, Grafana, or similar).
- Understanding of financial market structure and post-trade workflows.
What You Get
- A genuinely rich API to work with — not a thin FIX wrapper bolted onto a legacy system.
- Breadth across FX, Equities, and digital assets.
- Real ownership of the tech-to-business bridge.
- A genuinely tech-first operation.
- A small, senior team.
- Growth across the business.
- Competitive package — up to 30 days leave + bank holidays, private health insurance, pension, life insurance, dental/optical cashback, cycle to work, socials and offsites.
Our Hiring Process
We keep our process focused and respectful of your time. Our process follows three stages:
- Stage 1: Initial Conversation with Talent Acquisition - Video call, ~30-45 minutes.
- Stage 2: Team Conversation with one or two members of the Client Services team - Video call or In-person, interactive session, ~60 minutes.
- Stage 3: Leadership Conversation with CRO - Video call or In-person, ~60 minutes.
What to expect in each stage will be explained by Talent Acquisition if you're invited to interview. Throughout the process, we aim to keep momentum with no unnecessary delays between stages, and feedback typically comes within a few business days.
FIX Onboarding & Client Services in London employer: Reactive Markets
Reactive Markets is an exceptional employer, offering a dynamic remote work environment in the UK that fosters innovation and collaboration. With a strong emphasis on employee growth, you will have the opportunity to mentor fellow engineers while working with cutting-edge technologies in a supportive culture that values your contributions to high-performance trading solutions.
StudySmarter Expert Advice🤫
We think this is how you could land FIX Onboarding & Client Services in London
✨Tip Number 1: Tap Into Professional Networks
The finance world loves a good connection, so jump into industry-specific groups on platforms like LinkedIn where you can find discussions on financial controlling. Engaging in these communities can expose you to hidden job leads that aren't openly advertised!
✨Tip Number 2: Attend Finance Events and Conferences
Make it a mission to attend finance-related events and conferences, even virtual ones! This is a golden opportunity to network face-to-face with people from companies like Reactive Markets. You never know who might be your next boss or a crucial contact!
✨Tip Number 3: Showcase Your Expertise
Consider writing articles or sharing insights related to financial controlling or industry trends. Publish these on platforms like LinkedIn to establish yourself as a knowledgeable player in the field. This not only increases your visibility but also catches the attention of recruiters from Reactive Markets.
✨Tip Number 4: Apply Directly on Company Websites
Since you're going for a full-time gig, don't forget to keep an eye on the careers page of companies you're interested in, like Reactive Markets. Many companies prefer candidates who apply through their website as it shows genuine interest and makes your application stand out!
We think you need these skills to ace FIX Onboarding & Client Services in London
Some tips for your application 🫡
Show Off Your Numbers Game:In financial controlling, detail is everything! Make sure your CV showcases your proficiency with numbers—highlight any relevant experience in budgeting, forecasting, or working with financial software. Quantifying your past achievements will make you stand out, so don’t be shy about flaunting those impressive percentages or cost savings you've implemented.
Tailored Cover Letter is Key:Your cover letter is a chance to shine, especially for a full-time role. Use it to express your genuine interest in Reactive Markets and the specific impact you hope to make in financial controlling. Mention any relevant qualifications or experiences that align with the company’s goals, and don’t forget to show that you're ready for a long-term commitment!
Certifications Matter:List relevant certifications such as ACCA or CIMA on your CV. These qualifications not only showcase your dedication to the field but also your technical competence in financial principles. If you have any ongoing training or courses, make sure to mention those as well to demonstrate your commitment to continual learning in financial controlling.
Don’t Overlook Soft Skills:While numbers are crucial, so are those soft skills! Financial controllers need strong communication and analytical reasoning abilities. We recommend embedding examples of these skills in your CV and cover letter, like how you’ve successfully delivered financial reports to stakeholders or collaborated with teams to improve processes. Let’s show Reactive Markets how you can be a team player!
How to prepare for a job interview at Reactive Markets
✨Brush Up on Technical Skills
Make sure you're comfortable with key financial concepts, especially around forecasting, budgeting, and variance analysis. Sometimes, interviewers may throw in technical questions or case studies, so practicing these types of scenarios will help you shine!
✨Showcase Your Financial Acumen
If you've had experience with specific financial software like SAP or Oracle, make it known! Be ready to discuss how you used these tools to improve processes or reporting, as this hands-on knowledge can really set you apart in a full-time role with Reactive Markets.
✨Know Your Numbers
In full-time interviews, especially in financial controlling, be prepared for numerical reasoning tests or questions. Brush up on your mental maths and understand how to interpret and analyse financial statements on the spot, as this may come up during the assessment.
✨Connect with Company Goals
Familiarise yourself with Reactive Markets's financial objectives and any recent developments. During the interview, try to weave your understanding of their business model and challenges into your answers—this shows your genuine interest and alignment with their goals!
