JS Romania is looking for a Senior Performance QA Engineer to focus on the engineering experiences of tomorrow. In this role, you will work on delivering a modern, high-performance solution with a strong emphasis on performance, scalability, and observability for critical client systems.

What You'll Do

Determine performance test requirements and define the Performance Test strategy.
Create and maintain test artifacts (plans, reports, dashboards) in line with client expectations.
Develop and support load testing scripts and scenarios for front-end, back-end, and middleware systems using tools like Gatling and JMeter.
Execute load, stress, volume, and endurance tests as required.
Identify potential and ongoing performance and capacity issues, analyze findings, and provide actionable recommendations.
Analyze system performance, identify bottlenecks, and recommend tuning strategies.
Develop custom performance/load scripts for APIs and microservices using the Scala-based Gatling framework.
Define and implement SLAs, performance benchmarks, and KPIs for services.
Integrate performance testing into CI/CD pipelines (e.g., GitLab, GitHub Actions).
Collaborate with development, SRE, and QA teams to interpret results and drive improvements.
Monitor and report performance metrics using tools such as Grafana, Prometheus, InfluxDB, or cloud-native observability stacks.
Participate in incident analysis and postmortems when performance regressions are suspected.
Stay up to date with industry trends in performance engineering and microservice observability.

What We're Looking For

3+ years of extensive performance testing experience.
Strong understanding of performance bottlenecks and end-to-end performance measures (server response time, throughput, latency).
Experience with performance testing tools such as Gatling, JMeter, or Locust.
Solid experience with object-oriented or scripting languages, preferably Java.
Ability to set up performance testing processes from scratch and plan testing activities.
Experience with service-side monitoring tools such as AppDynamics, NewRelic, or Graphite.
Hands-on experience setting up and maintaining jobs and pipelines using CI tools (GitLab, Jenkins).
Strong English verbal and written communication skills.
2+ years of hands-on experience with Gatling or Gatling Cloud.
Strong knowledge of HTTP, REST APIs, WebSockets, and asynchronous event-driven systems.
Experience testing in microservices architectures (Kubernetes, Docker, Istio).
Proficiency in Scala or willingness to learn for custom Gatling scripting.
Familiarity with CI/CD workflows and integrating performance tests in pipelines.
Experience analyzing JVM-level metrics, logs, and APM tools (e.g., Datadog, New Relic).
Experience with cloud platforms (AWS, GCP, or Azure).
Solid understanding of load patterns, ramp-up strategies, and test environments.
Excellent problem-solving, communication, and collaboration skills.
Good analytical skills with strong interest in problem analysis and tuning.
Team player, motivated to solve complex tasks.
Self-motivated, disciplined, and results-oriented.
Strong attention to detail and accuracy.

Nice to Have

Experience in performance optimization and application tuning.
Familiarity with advanced observability and monitoring practices.

Technical Stack

Testing: Gatling, JMeter
Languages: Scala, Java
Infrastructure: Kubernetes, Docker, Istio
Monitoring/Observability: Grafana, Prometheus, InfluxDB, AppDynamics, NewRelic, Graphite, Datadog
Cloud: AWS, GCP, Azure
CI/CD: GitLab, Jenkins, GitHub Actions

Team & Environment

You will be part of a cross-functional development team within a One Team culture that values collaboration and progress, always exploring innovations and empowering each other to achieve more.

Benefits & Compensation

Strong community: Work alongside top professionals in a friendly, open-door environment.
Growth focus: Take on large-scale projects with a global impact and expand your expertise.
Tailored learning: Boost your skills with internal events (meetups, conferences, workshops), Udemy access, language courses, and company-paid certifications.
Endless opportunities: Explore diverse domains through internal mobility, finding the best fit to gain hands-on experience with cutting-edge technologies.
Flexibility: Enjoy radical flexibility – work remotely or from an office, your choice.
Care: Company-paid medical insurance, mental health support, and financial & legal consultations.