Senior Performance Test Engineer - k6 & JavaScript

• 8-10 years of experience in performance testing and quality engineering
• Strong proficiency in JavaScript (ES6+) with proven experience developing automated tests
• Hands-on expertise with k6 performance testing framework
• Experience testing REST APIs, GraphQL APIs and web applications
• Knowledge of performance engineering methodologies and performance tuning techniques
• Experience with CI/CD pipelines (GitHub Actions, GitLab CI, Azure DevOps or Jenkins)
• Proficiency using Git and collaborative development workflows
• Practical experience with Docker and Kubernetes
• Familiarity with cloud platforms (AWS, Azure or GCP)
• Experience using observability tools (Grafana, Prometheus, Application Insights or similar)
• Excellent problem-solving and analytical skills
• Strong communication and stakeholder management abilities
• Ability to influence technical direction and drive quality initiatives
• Passion for quality engineering and developer enablement
• Continuous learning mindset and curiosity about emerging technologies
• Ability to work effectively across global, distributed teams

Location: Warsaw

Contract Type: Contract (6 months)

• Work with cutting-edge performance testing tools including k6, Docker and Kubernetes
• Join a global, distributed team working on REST APIs, GraphQL APIs and web applications
• Shape technical direction and influence quality engineering practices across the organisation
• Gain hands-on experience with cloud platforms (AWS, Azure or GCP) and modern CI/CD pipelines
• Collaborate with stakeholders across multiple time zones on impactful performance engineering initiatives

Company Overview

Our client is a technology-focused organisation operating across global markets. They specialise in building scalable, high-performance systems and are committed to quality engineering and developer enablement. With distributed teams working across multiple regions, they foster a culture of continuous learning and technical excellence. The company invests in modern tooling and infrastructure, including cloud platforms, containerisation and observability solutions, to deliver robust applications that meet demanding performance standards.

They are seeking an experienced Senior Performance Test Engineer to join their team in Warsaw on a 6-month contract. This is an opportunity to work with modern performance testing frameworks and influence technical practices across a global engineering organisation.

Position Overview

As a Senior Performance Test Engineer, you will play a critical role in ensuring the performance, reliability and scalability of applications used by customers worldwide. You will design and develop automated performance testing frameworks using k6 and JavaScript, working closely with engineering teams to identify bottlenecks, optimise system performance and embed quality practices throughout the development lifecycle. Your work will directly impact the user experience and system stability across REST APIs, GraphQL APIs and web applications deployed on cloud infrastructure.

Benefits

While specific benefits details are to be confirmed, you'll be immersed in a technically advanced environment collaborating with a global team committed to quality engineering, continuous improvement and modern development practices across cloud infrastructure and performance testing.

,[ Design and develop automated performance test frameworks using k6 and JavaScript (ES6+) , Test REST APIs, GraphQL APIs and web applications to identify performance bottlenecks , Implement performance engineering methodologies and recommend tuning strategies , Integrate performance tests into CI/CD pipelines using GitHub Actions, GitLab CI, Azure DevOps or Jenkins , Collaborate with engineering teams using Git and established development workflows , Deploy and manage tests using Docker and Kubernetes in cloud environments , Monitor system performance using observability tools such as Grafana, Prometheus or Application Insights , Communicate findings and recommendations clearly to technical and non technical stakeholders , Influence technical direction and quality standards without direct authority , Support global teams across different time zones and geographical locations , Continuously learn and adopt emerging performance testing tools and techniques ] Requirements: Testing, JavaScript, REST API, GraphQL, Web applications, Performance tuning, CD pipelines, GitLab CI, Azure DevOps, Jenkins, Git, Docker, Kubernetes, Cloud platform, Azure, GCP, Grafana, Prometheus, Stakeholder management