Senior Load Test Engineer

Please note: Remote mode but later hybrid in Warsaw

Position Overview

We are looking for a Senior Load Test Engineer who is passionate about performance testing. You understand how systems work when many users use them at the same time. You know how to find problems before real users experience them. You can clearly explain what is wrong and why it needs to be fixed. You work independently, manage your testing process from start to finish, and care about keeping our platform fast and stable as it grows.

Key Responsibilities

• Plan and run load, stress, spike, and long-running tests on important parts of our platform.

• Study the results and find exactly where and why performance becomes worse.

• Work closely with backend engineers to understand the system and identify the real bottlenecks.

• Create and maintain performance test scripts that can be reused, stored in version control, and easily updated when the product changes.

• Add performance tests to CI/CD pipelines so problems can be detected early.

• Set performance goals and limits together with engineering and product teams.

• Watch how the platform behaves under load using monitoring tools and connect metrics with test results.

• Write clear reports and give practical recommendations to engineering teams.

Qualifications

• 5+ years of practical experience with performance and load testing for large production systems.

• Strong experience with tools such as k6, Gatling, JMeter, or Locust, including creating complex scripts from the beginning.

• Good understanding of backend systems, databases, and how infrastructure behaves under heavy load.

• Ability to read and understand metrics from tools like Grafana, Datadog, New Relic, or similar.

• Good knowledge of HTTP, WebSockets, and real-time communication protocols.

• Experience testing APIs under load, including authentication flows, many users at the same time, and stateful scenarios.

• Familiar with CI/CD pipelines and adding performance tests to automated build processes.

• Comfortable using Git and working in agile engineering teams.

Soft Skills

• Naturally curious — you like to understand why a system behaves in a certain way under pressure.

• Strong analytical thinking — you can review many metrics and quickly find the most important problem.

• Good communication — you can explain complex performance issues clearly to both developers and product managers.

• Self-motivated — you do not wait for someone to tell you there is a problem; you actively look for it.