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How is the RUM performance calculated ?


When a page is loaded, it sends one-two POST requests to a this pattern (exemple /rb_bf45848ori?app=4e957ef4c009cdd7).

- What is the purpose of this POST ? How it used for end to end latency measurement ?

- How is it different from the previous DynaTrace javascript tag ? The previous one did not use POST request if I am correct but used GET method.


Dynatrace Champion
Dynatrace Champion

Hi Shikha,

Both the Dynatrace RUM and the old AppMon UEM work in a similar fashion. A JavaScript agent is injected in the HTML of the web pages to be monitored (sometimes via GET request for the JS file, unless the code is added inline in full). The agent JS then does the user tracking on the page (captures clicks, page loads, keeps track of the session, etc.) and periodically sends the data captured in the form of POST requests.

So the POST requests you are seeing is just the RUM JS agent sending some of its data back to the Dynatrace cluster (this is the way the AppMon UEM works as well).

The first part of this page explains it more technically how the process works:

Best regards,


Hi Radu,

Thanks for the explanation, it has been helpful to understand the 'how' of Ruxit. I do have a followup question and would like to know your comments on it:

These POST requests (by millions) are decreasing our CDN Caching ratio (Akamai) – POST responses are not cached by default, hence sending our “Offloaded hits” KPI values to the ground.

  • May the content of the POST response be cached by intermediary CDN ? Can we enable it ?
  • Would this affect your RUM ? Would it improve/decrease latency measurement ? (compared to the previous dynatrace version).

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