Performance Tester

Role/Job title: Performance Tester Work Location: London Mode of working: Hybrid /2 days per week in office Contractor Rate: Market Rate Duration of assignment: 6 months (Likelihood of further extension Are you a proven Performance Tester with min 5 years of experience in Performance Testing / Non-functional Testing? Do you have strong experience with JMeter, LoadRunner, or NeoLoad? If so, our client is looking for an experienced Performance Tester to support the SSE Keystone transformation program, focusing on non-functional validation of billing systems, integrations, and dual run operations. The role involves validating system scalability, response time, throughput, and stability under real-world and peak load conditions to ensure business-critical billing processes operate without performance degradation. Required Essential Skills & Experience: * Ensure business-critical billing systems remain stable under peak loads by validating scalability, throughput, and response times using real-world workload modelling, preventing revenue-impacting failures. * Proactively identify and resolve performance bottlenecks through deep analysis using tools like Dynatrace/AppDynamics and deliver actionable tuning recommendations that improve system efficiency and reliability. * Support complex, high-volume, multi-system environments (including dual run scenarios) by designing and executing robust performance test strategies that ensure seamless integration and uninterrupted billing operations. Your responsibilities: * Analyse performance testing requirements including user load, throughput, transaction volumes, and usage patterns * Prepare Performance Test Strategy and Test Plan aligned to program milestones * Design and develop performance test scripts using JMeter and/or LoadRunner * Execute load, stress, endurance, and volume testing * Monitor application performance using tools such as Dynatrace, AppDynamics, or Azure Monitor * Analyse results and identify bottlenecks and system limitations * Prepare performance reports and tuning recommendations * Manage performance defects through to resolution * Support dual run validation ensuring stable billing operations * Validate high-volume transactions across multiple integrated systems Your Profile Essential skills/knowledge/experience: * 5–10 years of experience in Performance Testing / Non-functional Testing * Strong experience with JMeter, LoadRunner, or NeoLoad * Understanding of workload modelling and performance engineering concepts * Experience in Agile / DevOps environments * Experience in utilities or billing systems is highly desirable Desirable skills/knowledge/experience: * Strong leadership and team management skills * Excellent communication and stakeholder management * Ability to work in multi-vendor environment * Proactive risk management and decision-making