Senior Performance Test Engineer

Location: Warsaw, Poland (Hybrid – 2–3 days per week from office)

About the Role

We are looking for a Senior Performance Test Engineer to join our engineering team and help us build highly scalable, reliable, and resilient digital solutions. In this role, you will design and implement advanced performance testing strategies, develop automation frameworks, and work closely with engineering teams to identify bottlenecks and improve system performance.

You will play a key role in embedding performance engineering practices into the software development lifecycle, enabling teams to deliver high-quality products that perform reliably at scale.

This is an excellent opportunity for an experienced engineer who enjoys solving complex technical challenges, working with modern cloud technologies, and influencing engineering practices across distributed teams.

Key Responsibilities

• Design, develop, and maintain performance testing frameworks and automation solutions using JavaScript (ES6+).

• Create and execute performance, load, stress, and scalability testing strategies for modern applications.

• Develop and maintain performance test scenarios using k6.

• Test and analyze the performance of:

  • REST APIs

  • GraphQL APIs

  • Web applications and distributed systems

• Identify performance bottlenecks and provide actionable recommendations for optimization.

• Collaborate with developers, architects, DevOps, and product teams to improve system scalability and reliability.

• Integrate performance testing into CI/CD pipelines and engineering workflows.

• Support performance monitoring and analysis using observability platforms.

• Contribute to performance engineering standards, best practices, and continuous improvement initiatives.

• Work effectively with global, distributed engineering teams and communicate technical findings to both technical and non-technical stakeholders.

Required Skills & Experience

• Strong proficiency in JavaScript (ES6+).

• Proven experience building automated test frameworks and reusable testing solutions.

• Hands-on experience with k6 performance testing.

• Strong understanding of performance engineering methodologies, including:

  • Load testing

  • Stress testing

  • Scalability testing

  • Performance analysis and tuning

• Experience testing modern web applications and APIs, including:

  • REST APIs

  • GraphQL APIs

• Experience integrating automated tests into CI/CD pipelines, using tools such as:

  • GitHub Actions

  • GitLab CI

  • Azure DevOps

  • Jenkins

• Strong experience with Git and collaborative software development workflows.

• Solid understanding of software engineering principles and modern development practices.

• Excellent analytical and problem-solving skills.

Cloud & Infrastructure Experience

Experience working with modern cloud and infrastructure technologies:

• Docker and containerized environments.

• Kubernetes and cloud-native architectures.

• At least one major cloud platform:

  • AWS

  • Microsoft Azure

  • Google Cloud Platform (GCP)

• Experience with observability and monitoring tools, such as:

  • Grafana

  • Prometheus

  • Application Insights

  • Similar monitoring and analytics platforms

Soft Skills & Mindset

• Strong communication and stakeholder management skills.

• Ability to influence technical decisions and drive improvements without direct authority.

• Passion for quality engineering, automation, and developer enablement.

• Continuous learning mindset and curiosity about emerging technologies.

• Ability to collaborate effectively across international and distributed teams.

• Comfortable working independently while contributing to a highly collaborative engineering culture.