We are looking for an experienced Performance Tester to join a team working on banking applications. The main responsibility will be designing and writing performance tests using k6, as well as executing performance testing of systems with k6 and supporting integration testing.This is a time-based contract until the end of June 2026, with the possibility of extension.IN SHORT:🌎 100% remote or from the office (Wrocław, Bielsko-Biała) - You choose!💰 110 - 135 PLN/h (Middle/Senior)☑️ B2B contractYour Daily MissionsDesigning and executing performance tests (load, stress, endurance) using k6 (current tests are written in Gatling; understanding of Gatling is a plus).Creating and maintaining test scripts in k6 (Gatling is welcome as an additional skill).Performing integration and manual testing of banking systems when needed.Analyzing test results and identifying performance bottlenecks.Collaborating with development and DevOps teams to optimize system performance.Preparing reports and presenting test results to stakeholders.Integrating performance tests into CI/CD pipelines.Supporting the team in resolving performance and integration issues.The Essentials We're SeekingMinimum 3 years of experience in performance testing.Hands-on experience with k6 for performance testing.Experience in integration testing.Knowledge of REST APIs and microservices architectures.Ability to analyze system metrics (CPU, memory, response times).Experience with monitoring tools (e.g. Grafana, Prometheus).English at minimum B2 level.Nice to HaveKnowledge of Gatling (additional advantage).Experience in the banking or FinTech sector.Familiarity with Continuous Delivery practices and Agile environments.Experience with Docker and/or Kubernetes.Knowledge of scripting languages (JavaScript, Python).Reasons Why You Would Enjoy Working With UsWork on advanced banking systems.Collaboration with an experienced QA team.Opportunity to develop skills in the area of performance testing.We work in the latest technologies and with international clients, and our projects are polished from < to /> - learn about some of the projects we have completed.We organize TechTalks, meet-ups and create guilds where we exchange knowledge - you can learn a lot from your teammates.We have a close-knit team and we make sure to have regular integrations - we often go out to celebrate together.You can work remotely or choose to work from our offices in Wroclaw or Bielsko-Biala. However, we count on your openness to occasionally visit the office for team meetings or client visits, or possible occasional trips to the client's headquarters.You can adjust your working hours to suit your needs, starting your day between 7:00 and 10:00 am.You can work with great specialists in their fields who also have a sense of humor and other after-hours hobbies. It is the people who create the unique atmosphere and relaxed atmosphere at CSHARK.We have a flat structure - we are not a corporation and don't want to be one 🙃.We offer bonuses for employee referrals (from 3000 PLN to 7000 PLN).We organize remote English classes and provide access to the company library. You can also become an author/author of articles published on our technical blog - https://cshark.com/blog/.