Which parameter does RUM NOT capture?

Real User Monitoring (RUM) is a performance measurement tool that gathers data from user interactions with web applications, providing insight into the user experience from the actual client side. It captures various metrics that reflect how users experience your application, including rendering times on various platforms.

Regarding the parameters captured by RUM, Chrome Browser Rendering Time, iOS Rendering Time, and Android Rendering Time all relate to the client-side experience. These metrics focus on how long it takes the user's browser or device to render the application visually.

In contrast, back-end web application response time pertains to the performance of the server-side components of an application. This metric is typically captured through Server-side Monitoring (APM) rather than RUM. While RUM focuses on how the end-user perceives the application from their device, back-end response time is about how quickly the server processes requests and delivers data to the client.

Therefore, capturing back-end web application response time is outside the scope of RUM, making it the correct choice in this context.