Senior Rapid Application Engineer London ·

Internal Job Level: Senior Associate

Reports to: Rapid Application Development Manager

Job Overview

In this role you will be working with the Product, Infrastructure, QA, and Operations teams to solve complex problems at speed. Unlike our Low Latency team who build the exchange engine itself, the RAD (Rapid Application Development) team lives at the intersection of troubleshooting, innovation, and operational efficiency. You’ll be investigating the toughest production issues, validating new trading technology approaches through rapid prototyping, and building the internal tools and test frameworks that keep Aquis running smoothly. You’ll be part of a small, high-impact team that combines detective work with creative engineering. One day you'll be diagnosing an intermittent issue in how we handle high-volume order processing; the next, you'll be building a POC for a new trading feature or designing a performance test suite that simulates real market stress. You thrive in environments where problems are ambiguous, priorities shift quickly, and your ability to communicate findings clearly to non-technical teams (QA, Product, Sales) is as important as the code you write. To succeed as a Senior RAD Engineer, you will be a proponent of agile principles and modern software best practices. You can produce detailed technical work in OOP and collaborate effectively with other development teams to produce code of high quality. Ideally, you will have worked in critical systems development and have direct experience investigating and resolving production issues in high-performance environments. You should be comfortable with operational thinking, understanding not just what systems do, but why they fail and how to prevent it.

Responsibilities and Duties

• Lead rapid prototyping and validation efforts: Design and implement proof-of-concept solutions for new trading algorithms and system approaches, with emphasis on speed-to-market and iterative feedback from stakeholders.
• Drive troubleshooting investigations: Investigate complex production issues, performance anomalies, and system failures; establish reproducible test cases and diagnostic harnesses to validate root causes; communicate findings clearly to non-technical teams and document root causes for the broader engineering team.
• Build internal tools and frameworks: Develop tools that improve operational efficiency, such as test suites, performance benchmarking frameworks, reproduction environments, diagnostic utilities, and internal dashboards that enable Ops and QA teams to resolve issues faster and validate fixes reliably.
• Mentor mid-level RAD engineers: Provide technical guidance and code review for junior team members; help elevate issues appropriately and develop their investigative and prototyping skills.
• Establish and maintain RAD engineering standards: Champion best practices for MVP development, testing, deployment automation, and documentation; ensure RAD-produced code meets security and reliability standards despite the emphasis on speed.
• Apply deep technical analysis: Use computer science principles, engineering techniques, and mathematical analysis to break down complex problems in trading technology, market data flows, and system performance.
• Participate as a Subject Matter Expert: Review and advise on software components, system designs, and architectural decisions; act as the voice of operational realities in engineering discussions.

Skills and Experience

Essential

• 10+ years professional development experience with C++11 or later, building performant, scalable applications in production environments.
• 6+ years hands-on experience with networking fundamentals (UDP, multicast, TCP, etc.), messaging systems, and algorithmic problem-solving.
• 6+ years working on Linux systems, including kernel concepts, system tuning, and debugging tools (gdb, strace, perf, etc.).
• Proven troubleshooting and investigative skills: Demonstrated ability to diagnose complex issues in production systems, whether via logs, memory dumps, or instrumentation, and communicate findings clearly to both technical and non-technical audiences.
• Expert in creating reproducible test cases: Skilled at building reliable test environments, isolating issues, and creating frameworks that help others validate fixes and prevent regressions.
• Strong understanding of modern development best practices: Continuous integration, automated testing, code review discipline, and version control workflows.
• Kanban and CI/CD: Comfortable with Kanban workflow, continuous integration, Jira, and rapid iteration cycles.
• Git and version control: Professional-grade proficiency.
• SQL: Ability to query and analyse data from our systems.
• Experience delivering under time pressure: Ability to prioritize effectively, ship MVPs quickly, and iterate based on feedback without perfectionism compromising progress.
• Proficient with AI tools in development: Comfortable using LLMs, coding assistants, and AI-powered tools to enhance productivity, debug code, generate documentation, and solve problems faster.

Desired

• Python development proficiency: Strong ability to write automation scripts, diagnostic tools, and performance analysis scripts in Python.
• Shell scripting (Bash): For system-level automation and analysis.
• Performance analysis and optimization: Experience with profiling tools (perf, flame graphs, etc.) and track record of identifying and fixing performance bottlenecks.
• Experience building test infrastructure: Previous work on test frameworks, load testing suites, or performance benchmarking systems.
• Capital markets knowledge: Familiarity with exchange technology, FIX protocols, market data formats, or trading workflows.
• Docker/containerization basics: Growing relevance for deployment and testing.
• QuestDB or Dolt: Time-series or version-controlled database experience.

Mindset and Methodology

• Operational mindset: You think about systems not just from a code perspective, but from "how will this be operated and what could go wrong?" You understand that production incidents are learning opportunities.
• Comfortable with ambiguity: RAD work often starts without a clear specification. You're skilled at gathering requirements, validating assumptions, and delivering value incrementally.
• Strong communicator: You can explain technical findings to non-technical stakeholders without dumbing down the substance. Your diagrams, summaries, and postmortems help the whole organization learn.
• Excellent team player: You collaborate across silos (Product, Infrastructure, Ops) and help other teams succeed, not just your own.
• Autonomous yet collaborative: You drive investigations independently but escalate proactively when needed. You know when to ask for help and when to dig deeper.
• Delivers incrementally: You ship fast and iterate. You understand that a 70% solution delivered today is often better than a perfect solution delivered next month. You recognize that validation and feedback drive better outcomes than endless upfront planning.
• Drive to solve complex problems: Above all, you're energized by the challenge of diagnosing the difficult bugs and building tools that make the platform more reliable and efficient.

About Aquis Exchange

Aquis Exchange ("Aquis") is Europe's challenger exchange, creating better markets for a modern economy. Aquis has market-leading technology and innovative rules for trading, and offers primary listings and secondary trading of equities, along with global licensing of proprietary technology. Aquis consists of four divisions: Aquis Markets operates lit and dark order books, covering 16 European markets. For its lit books, Aquis uses a subscription pricing model which works by charging users according to the message traffic they generate, rather than a percentage of the value of each stock that they trade. Aquis Technologies is the software and technology division of Aquis. It focuses on building better markets via the creation and licensing of cutting-edge, cost-effective exchange infrastructure technology and services, including matching engine and trade surveillance solutions. Aquis Stock Exchange ("AQSE") is a stock market providing primary and secondary markets for equity securities. It is authorised as a Recognised Investment Exchange, which allows it to operate a regulated listings venue. The AQSE Growth Market is divided into two segments "Access" and "Apex".