Replay performance impacts

Last Updated:

When considering enabling Session Replay (beta), it’s important to understand how Session Replay might influence your app’s speed and overall performance.

Effects of data transmission

To conserve network bandwidth, Pendo’s standard data collection and transmission process compresses and transmits data every two minutes.

With Session Replay enabled, data transmission becomes more frequent, and data is transmitted as often as every five seconds. This increase is due to the additional data we capture, such as mouse movement events.

Depending on the complexity of the interactions captured in a replay, especially if your page has a high CPU load, it’s possible the addition of Session Replay could have a negative impact on performance.

Similarly, when visitors access your app on a mobile device, there’s a potential impact on battery life. If you receive reports of such issues, you can address this by excluding these visitors from capture using the most recent device type does not equal mobile segment rule on the Replay Settings page.

Web workers for enhanced performance

To minimize the risk of your app’s performance being compromised by replay captures, we employ a technique called web workers. Web workers are background scripts that tackle resource-intensive tasks, which prevents your app from slowing down.

Pendo offloads replay captures to these web workers to reduce any potential impact on your app’s main thread. This allows us to capture visitor interactions without impacting your app’s responsiveness.

If you have a Content Security Policy (CSP) configuration for Pendo, it’s crucial to update it to avoid potential conflicts with web workers and ensure your app’s performance remains unaffected. For more details, see CSP configuration.


To alleviate any potential performance concerns, we recommend enabling Session Replay for a smaller set of internal users so that you can monitor performance effectively and make informed decisions. To learn more, see Segmentation.

Was this article helpful?
0 out of 0 found this helpful