Firefox HAR record¶
Firefox has a built-in extensions which allows to easily record requests and responses and export them as HAR format.

Quick Video explaining how to record HTTP requests with Firefox
How to record¶
The following procedure explains how to record HTTP as an HAR file with Firefox:
- Start Firefox,
- Then press CTRL + SHIFT + P to start an incognito session,
- Press CTRL + SHIFT + I to display the developer toolbar,
- Select Toolbox options tab, and check enable persistent log,
- Go back to_Network_ tab
- Navigate to record HTTP traffic,
- Right-click on any request and select Save All As HAR.
Info
In case you do not have Firefox, you can download our sample HAR file.
Create Virtual User: Import HAR¶
Upload the newly created HAR file to create a virtual user:

Simply drop the file in the HAR area or use the Upload new HAR file button and hit Next.
Warning
If a response/request is truncated by Firefox follow this procedure:
- Type about:config in the URL bar to open the configuration page
- Increase the values of those parameters ("0" or "-1" won't configure them as unlimited) :
devtools.netmonitor.requestBodyLimitdevtools.netmonitor.responseBodyLimit
Before uploading, you can adjust the import options: ad blocker, static resources and think times.