# Reason Dynatrace is smart enough to not capture RUM during Load-Testing?

**URL:** <https://community.dynatrace.com/t/reason-dynatrace-is-smart-enough-to-not-capture-rum-during-load-testing/20215>\
**Category:** Real User Monitoring\
**Tags:** real-user-monitoring-classic\
**Created:** [September 3, 2020, 3:05am UTC](https://community.dynatrace.com/t/reason-dynatrace-is-smart-enough-to-not-capture-rum-during-load-testing/20215 "2020-09-03T03:05:51Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![waikeat\_chan](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/waikeat_chan/32/33405_2.png) [@waikeat\_chan](https://community.dynatrace.com/u/waikeat_chan)\
**Post date:** [September 3, 2020, 3:05am UTC](https://community.dynatrace.com/t/reason-dynatrace-is-smart-enough-to-not-capture-rum-during-load-testing/20215/1 "2020-09-03T03:05:51Z")

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I’ve run load-test with Jmeter as well as Neoload for the past two years, happy that everytime I don’t need to configure or do anything, and yet confident that Dynatrace won’t capture the RUM.

So just out-of-curiosity, what is the key-feature/distinguish-er Dynatrace is using? I want to know this so that in future I won’t run into unfortunate circumstance where load-testing somehow accidentally wasted/burn-out the DEM Unit of Customer license.

Best Regards,

Wai Keat

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**Author:** ![Enrico\_F](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/enrico_f/32/23774_2.png) [@Enrico\_F](https://community.dynatrace.com/u/Enrico_F)\
**Post date:** [September 3, 2020, 5:59am UTC](https://community.dynatrace.com/t/reason-dynatrace-is-smart-enough-to-not-capture-rum-during-load-testing/20215/2 "2020-09-03T05:59:38Z")

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RUM requires that the web client loads and executes Javascript. As long as your load testing tool does not simulate a fully-fledged browser with enabled Javascript runtime you will not get user session data.

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**Author:** ![Julius\_Loman](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/julius_loman/32/51_2.png) [@Julius\_Loman](https://community.dynatrace.com/u/Julius_Loman)\
**Post date:** [September 3, 2020, 7:15am UTC](https://community.dynatrace.com/t/reason-dynatrace-is-smart-enough-to-not-capture-rum-during-load-testing/20215/3 "2020-09-03T07:15:31Z")

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In addition to [@Enrico Favretto](https://answers.dynatrace.com/users/3956/view.html)’s answer - Dynatrace also ignores JavaScript injection into requests based on user-agent header in your requests. There are certain user-agent strings causing Dynatrace not to inject the RUM JavaScript. JMeter tests are purely HTTP request without JavaScript execution. If you will spin up browser in your tests for example using Selenium, you will find your user sessions.

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**Author:** ![waikeat\_chan](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/waikeat_chan/32/33405_2.png) [@waikeat\_chan](https://community.dynatrace.com/u/waikeat_chan)\
**Post date:** [September 6, 2020, 6:34am UTC](https://community.dynatrace.com/t/reason-dynatrace-is-smart-enough-to-not-capture-rum-during-load-testing/20215/4 "2020-09-06T06:34:19Z")

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Ah, I see. I only ever perform Load-Test on Jmeter and Neoload before, but never with Selenium.

Thanks.