Showing results for 
Show  only  | Search instead for 
Did you mean: 

Phasing out of 3rd party cookies impact on RUM



With respect to Google phasing out 3rd parties cookies, how would this impact Dynatrace RUM?

Understand from the documentation that that the following cookies are  all first-party cookies:

Cookie Structure Expires Max size Purpose


v4 session state:

Possible keys include:

  • srv

  • sn

  • mvisitor

  • msn

  • perc

  • ol

  • mul

  • app:<appID>

v4 example:


No set limitation, but usually less than 100 B

Tracks a visit across multiple requests.


<numeric value>


5 B

Measures server latency for performance monitoring.




58 B

Required to identify proper endpoints for beacon transmission; includes session ID for correlation.


<URL-encoded action name>


Max number of characters in the URL

Serves as an intermediate storage for page-spanning actions. This cookie is used to save user action names, such as Click on Login, across different pages. This is required because page loads result in JavaScript code restart, so all contextual information must be stored in cookies.


The dTValidationCookieValue string.

Deleted after a few milliseconds; no expiry date set

Length of dTValidationCookieValue string, that is 23

Used to determine the top-level domain.




4 B

Determines if the RUM JavaScript should be deactivated due to cost and traffic control or overload prevention.



Session or permanent2

45 B

Contains the visitor ID to correlate sessions.




27 B

Specifies the session timeout.


But how are these cookies being injected such that they are first party cookies?

  • Sever-side injection or domain matching?


In other post, one of the replies stated that "actually dtCookie is injected on server-side and its injection is unrelated to the presence of the RUM script".

If so are the other cookies injected on server-side too?

Based on another comment is seems to suggest that if the RUM script is not loaded, then only dtCookie is injected. This also suggest that the other cookies are injected by the RUM script - would this make them 3rd party cookies?

And also does this server-side injection require OneAgent? If i am using agentless monitoring, are dtCookie still injected on server-side?


Sorry for the list of questions, & thanks in advance.


look at the below portion in the beginning of the file `ruxitagentjs_xxxxxxxxxxxxxxxx.js` `.concat("__dtCookie","=")` then it's looks injected in the client side

 Copyright and licenses see */
(function(){function Ga(){document.cookie="".concat("__dTCookie","=").concat("1",";SameSite=Lax");var Pa=-1!==document.cookie.indexOf("__dTCookie");document.cookie="".concat("__dTCookie","=").concat("1","; expires=Thu, 01-Jan-1970 00:00:01 GMT");


I wish this help you.

Certified Dynatrace Professional | Certified Dynatrace Services - Observability | Dynatrace Partner

Thanks for the response, i see so dtCookie is client side? 

Even so, it is still 1st party cookie right? hence Dynatrace RUM is not affected in anyway by Google phasing out on 3rd party cookies?


it depends on type of injection, if you're using RUM auto-injection mostly it wouldn't affected by Google because ruxitagent uses the same domain name of your web app and send data back to the same Origin, otherwise if you using manual injection or your app data will be sent using CORS which means you'll using different domain for specific activegate then it's mostly would be affected by Google.

in this case you've to check the rules and policies of Google

Certified Dynatrace Professional | Certified Dynatrace Services - Observability | Dynatrace Partner

Just to clarify further by RUM auto-injection you are referring to OneAgent and by manual injection you are referring to agentless monitoring?


yes exactly I'm referring to agentless monitoring when mentioned manual injection, but take in consideration regardless what you're using for injection (auto or manual) the origin of the ruxitagent.js is it using the same domain different domain this is the main idea.

I hope this notes be useful for you.

Certified Dynatrace Professional | Certified Dynatrace Services - Observability | Dynatrace Partner

Featured Posts