Hi Bevara,
You can use the Advanced Search option to find how many REST activities are used in your application.
In the left navigation panel, you will see options like App and Edit. Click on Edit, where you can find the Advanced Search option. In the search settings, select Integration Microflow Activities, then enable the Call REST Service activity. After that, click on the Find button to see the results.
Yes, indeed there is a search option to find all the usages of rest call activity.
Go to edit option in studiopro -> find advanced -> integration activities.
You'll get all the list of microflows where the rest call activity is used.
Use /rest-doc/ post application url to find published service
Eg https://xyz-test.mendixcloud.com/rest-doc/
For REST Service activity use the advance option in studio pro