Configure resource capture

Latest Dynatrace
How-to guide
3-min read
Published May 07, 2026

With Dynatrace Session Replay, stylesheets are captured and stored during user session recording. You don't have to keep your CSS files at a publicly accessible location, mark the resources as modified, or give permissions to a process that can access the protected stylesheets. It's an entirely automated process that ensures that resources are captured and made available for future replay.

Resource capture for Session Replay is activated by default.

Activate resource capture

To activate and configure resource capture

Go to Web.
Select the application that you want to configure.
In the upper-right corner of the application overview page, select More (…) > Edit.
From the application settings, select Capturing > Resource capture for Session Replay.
Turn on Enable resource capture.
Optional To avoid capturing resources for certain pages, select Add exclusion rule, enter a regular expression, and then select Add rule.
The exclusion rules are processed as follows.
If a URL matches an exclusion rule, the rule is applied and the subsequent rules are ignored.
If a URL doesn't match any listed rule, all resources are captured.
If Session Replay is activated and no URL exclusion rules are defined, all CSS resources are eligible for recording.

Notes and limitations for resource capture

If a resource hasn't been captured or is unavailable in the Dynatrace resource storage, this resource is retrieved from the original source.
Images and fonts aren't captured. During session playback, they're retrieved from the original location, so certain restrictions apply. To enhance Session Replay playback, install the Session Replay browser extension from the Chrome Web Store. The extension allows proxy loading of resources and is useful when font and stylesheet resources are loaded from HTTPS origins or resources are loaded from HTTP origins.
Dynatrace doesn't capture a resource that is bigger than 3 MB.
The default retention time for captured resources is 35 days.
Dynatrace captures resources for up to 0.1% of user sessions recorded with Session Replay. This is usually enough to properly replay user sessions, as a resource captured for one session is reused for all other sessions. However, capturing all resources for a low-traffic application might take some time.

Calculate sessions with captured resources

See the formula and example below to calculate the number of user sessions for which Dynatrace captures resources.

Sessions with captured resources = Total sessions × RUM cost and traffic control × Session Replay cost and traffic control × 0.1%

Parameter	Explanation	Example value
Total sessions	Total number of user sessions in your application	1,000,000
RUM cost and traffic control	Percentage of user sessions captured and analyzed with RUM	50%
Session Replay cost and traffic control	Percentage of user sessions recorded with Session Replay	10%

In our example, resources are captured for 50 user sessions (1,000,000 × 50% × 10% × 0.1% = 50).