Real user monitoring (RUM) is a passive monitoring technology that records all user interaction with a website or client interacting with a server or cloud-based application.
[1] Monitoring actual user interaction with a website or an application is important to operators to determine if users are being served quickly and without errors and, if not, which part of a business process is failing.
Real user monitoring data is used to determine the actual service-level quality delivered to end-users and to detect errors or slowdowns on websites.
[3] The data may also be used to determine if changes that are propagated to sites have the intended effect or cause errors.
In most cases, a form of JavaScript is injected into the page or native code within the application to provide feedback from the browser or client.