Performance Test Engineer - 18 month maximum contract role

Introduction

We are looking for an experienced Performance Test Engineer to join our Engineering & Architecture, Core Services team on an 18 month maximum term contract. This newly created position will build a performance and load testing framework and define the overall test strategy.

Responsibilities

• Define and implement comprehensive performance testing strategies, including best practices and standards.
• Develop and execute a range of tests (load, stress, endurance, scalability) for C#/.NET applications deployed in AWS using k6.
• Analyse system behaviour under load and provide actionable insights to improve performance.
• Collaborate with engineering teams to integrate performance testing into the development lifecycle.
• Build platforms from scratch, ensuring they are designed and tested to perform effectively under real world conditions.
• Lead performance and non functional testing across critical trading platforms, ensuring they remain scalable, resilient, and responsive.
• Design, develop and execute performance tests; build and maintain reusable performance test frameworks and scripts.
• Analyse test results to identify bottlenecks across application, database, and infrastructure layers.
• Collaborate with developers to diagnose performance issues and validate fixes.
• Integrate performance tests into CI/CD pipelines.
• Define and monitor performance KPIs, SLAs, and non functional requirements.
• Produce clear performance test reports with actionable recommendations.
• Support capacity planning and performance tuning initiatives.
• Advocate for performance testing best practices across teams.

Qualifications

• 5+ years of experience as a performance tester.
• Strong experience with performance and non functional testing.
• Extensive experience with k6 (JavaScript based scripting).
• Experience testing C#/.NET applications.
• Solid understanding of AWS cloud architecture and distributed systems.
• Experience with REST APIs, HTTP protocols, and JSON.
• Ability to analyse performance metrics (CPU, memory, latency, throughput, error rates).
• Familiarity with CI/CD tools (e.g., GitHub Actions).
• Strong problem solving and communication skills, able to communicate effectively with stakeholders.
• Understanding of financial services or stockbroking platforms is beneficial but not essential.

Benefits

• Accrue 5 additional annual leave entitlements each year called My Days, plus 5 extra leave days after 12 months.
• Birthday off.
• Free annual charity day.
• Access to zero cost trades on CMC Markets Invest for staff and family.
• Continuous learning through L&D offering covering technical and performance training.
• Unlimited access to a dedicated benefits & wellbeing hub.
• Collaboration opportunities in a supportive office culture.
• Free breakfast cereals, condiments and coffee.
• Culture club providing fitness, cooking, socialising and recreational activities.

Equal Opportunity Employer

CMC Markets is an equal opportunities employer and is committed to creating a diverse and inclusive workplace where all employees feel valued.