We are looking for a Performance Tester to join our team in Warsaw. This is an on-site role for a specialist with strong experience in performance testing and system optimization. Responsibilities: Plan, execute, and analyze performance tests (Load, Stress, Endurance, Spike). Configure test environments and ensure adequate resources (servers, databases, networks). Monitor system metrics (CPU, memory, response time, throughput) and identify bottlenecks. Create realistic test scenarios reflecting user behavior. Report findings with recommendations and perform regression testing after fixes. Requirements: 3+ years of performance testing experience. Hands-on experience with tools: JMeter, LoadRunner, Gatling, SoapUI, SQL, Linux, Windows. Knowledge of network protocols (HTTP/S, TCP/IP, WebSocket), REST/SOAP APIs, and web services. Ability to analyze results, optimize systems, and work independently or in a team. Languages: Polish (fluent), English (fluent) Nice to Have: Pr...