Senior Performance Test Engineer k6 & JavaScript

Location: Warsaw
Contract Type: Contract

Job Type: Hybrid

• Lead performance testing initiatives using k6 and modern JavaScript frameworks
• Work with cutting-edge cloud infrastructure including Docker Kubernetes and AWS/Azure/GCP
• Influence technical direction across global distributed engineering teams
• Shape quality engineering practices and developer enablement strategies
• Collaborate with stakeholders to drive performance optimisation across REST APIs GraphQL and web applications

Our client is an established technology organisation operating across global markets focused on delivering high-quality software solutions at scale. They prioritise engineering excellence continuous improvement and collaborative working practices. The company supports distributed teams and invests in modern tooling and infrastructure to enable their engineers to deliver impactful results. With a commitment to quality engineering and developer enablement they create an environment where experienced professionals can influence technical direction and drive meaningful change.

They are seeking an experienced Senior Performance Test Engineer to join their team in Warsaw on a contract basis. This role offers the opportunity to work with modern performance testing tools and cloud technologies while collaborating with engineering teams across different time zones.

As a Senior Performance Test Engineer youll play a critical role in ensuring system reliability and performance across multiple applications and services. Youll develop automated performance testing frameworks using k6 and JavaScript working closely with engineering teams to identify bottlenecks optimise system performance and establish best practices. Your work will directly impact the quality and scalability of production systems helping the organisation deliver robust solutions to their users. This position requires strong technical skills combined with the ability to communicate effectively with stakeholders and influence technical decisions across teams.

• Design and develop automated performance testing frameworks using k6 and JavaScript (ES6)
• Test REST APIs GraphQL APIs and web applications for performance scalability and reliability
• Implement performance testing within CI/CD pipelines using GitHub Actions GitLab CI Azure DevOps or Jenkins
• Analyse performance metrics using observability tools such as Grafana Prometheus and Application Insights
• Collaborate with engineering teams to identify performance bottlenecks and recommend optimisation strategies
• Establish performance engineering methodologies and tuning practices across the organisation
• Work with Docker Kubernetes and cloud platforms (AWS Azure or GCP) to support testing infrastructure
• Manage code repositories and collaborative workflows using Git
• Communicate findings and recommendations clearly to technical and non-technical stakeholders
• Influence technical direction and drive quality engineering initiatives without direct authority
• Support global distributed teams across different time zones

• 10 years of experience in performance testing and quality engineering
• Strong proficiency in JavaScript (ES6) with proven experience developing automated tests and frameworks
• Hands-on expertise with k6 performance testing tool
• 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
• Experience with Docker and Kubernetes
• Familiarity with cloud platforms (AWS Azure or GCP)
• Experience using observability tools such as Grafana Prometheus or Application Insights
• Excellent problem-solving and analytical skills
• Strong communication and stakeholder management abilities
• Ability to influence technical direction without direct authority
• Passion for quality engineering and developer enablement
• Continuous learning mindset
• Ability to work effectively across global distributed teams

While specific benefits details are being finalised youll join an organisation that values engineering excellence and supports professional growth. Youll work in an environment that encourages continuous learning collaboration across global teams and the opportunity to influence technical practices. The role offers exposure to modern cloud technologies performance testing tools and the chance to work with distributed engineering teams on meaningful technical challenges.

To apply for this role please submit your CV using the form below or email