Senior Software Engineer in Test IV (TS/Python)

Company at a Glance OpenX is focused on unleashing the full economic potential of digital media companies. We do this by making digital advertising markets and technologies that are designed to deliver optimal value to publishers and advertisers on every ad served across all screens. At OpenX, we have built a team that is uniquely experienced in designing and operating high-scale ad marketplaces, and we are constantly on the lookout for thoughtful, creative executors who are as fascinated as we are about finding new ways to apply a blend of market design, technical innovation, operational excellence, and empathetic partner service to the frontiers of digital advertising. At OpenX Poland, we are looking for a talented, communicative, and curious Software Development Engineer IV in Test to join our team in Cracow, Poland. You will join the Core Exchange development team at OpenX. Our exchange handles billions of ad requests every day, connecting thousands of publishers with demand partners across the global advertising ecosystem. The platform runs in the cloud across multiple regions and operates at a scale where performance, reliability, correctness, and every millisecond matter. You will be part of a cross-functional product engineering team focused on business-critical workflows that support how advertising transactions are configured, reviewed, processed, and validated across OpenX. These tools help users manage business rules, review transaction setup, and keep platform behavior aligned with business agreements and financial processes. In this senior UI-focused SDET role, you will take strong ownership of test automation for TypeScript-based frontend applications, while also contributing to API integration and end-to-end testing using Python and pytest. This role is well suited for someone who wants to make UI test automation their primary area of expertise while also working regularly in the API testing area. In practice, we expect the work to be roughly two-thirds UI test automation and one-third API testing. The primary stack for this role includes: TypeScript, Playwright, React-based applications, Python APIs, Pytest, Spinnaker (CI/CD). The broader engineering environment also includes Node.js, GraphQL, Java, Go, GCP, and Kubernetes. You do not need to be an expert in all parts of our backend stack, but you should be comfortable collaborating with backend engineers and understanding service-level behavior. Prior AdTech experience is helpful, but not required. Team setup You will join a cross-functional product engineering team with a dedicated Product Manager, Scrum Master, Engineering Manager, QA engineers, frontend and backend engineers, and regular collaboration with UX designers. This setup gives you direct access to product context and a real opportunity to influence business requirements, solution design, test strategy, and release quality. On a daily basis, we use the Scrum framework with an open-minded attitude to adapt the process to our needs. Within the team, you will have the opportunity to work closely with other SDETs focusing on different domains, as well as be part of the QA Guild focused on making impactful changes to our tools and processes.