Mariusz Stanisz
Senior Software Engineer
Software Mansion
Mariusz Stanisz is a Senior Software Engineer at Software Mansion, where he focuses on React Native performance and brownfield integrations. He authored a blog post included into React Native documation for the new Performance Panel introduced in RN 0.83, helping developers understand and diagnose performance issues in their applications. Mariusz previously spoke at App.js 2024, presenting "Brownfield Integration – Exploring the Limits," and later led a React Native performance workshop at App.js 2026. He enjoys sharing practical techniques for finding performance bottlenecks and believes that many React Native performance issues originate in React itself rather than the native layer. Outside of software, he's also a licensed Kraków city guide and is currently building an app to help people explore the city.
React Native: Performance Analysis & Optimization
Workshop
Performance can become a serious challenge as React Native applications grow. But before you optimize the code, you need to understand what causes the problem.
Based on the engineering patterns we use at Software Mansion for large-scale products, this hands-on workshop teaches you how to diagnose performance problems in React Native applications. We will use tools such as Flashlight, the React Native Performance panel, and the Profiler to identify the root causes of UI lag and understand where performance issues come from.
Key Takeaways:
- Use the React Native Profiler to identify unnecessary re-renders and expensive component work.
- Use the Performance panel to find heavy JavaScript operations.
- Use Flashlight to measure CPU and memory use.
- Compare FlatList, FlashList, and Legend List using real performance data.
- Build a clear process for diagnosing performance problems before deciding how to fix them.