The SciCat seachAPI is the SciCat metadata catalogue standardised API for communication between SciCat and the PaN portal, built on top of the Loobpack framework.
The searchapi configuration is set by the .env file. For an extensive list of available options see here.
In the default configuration .env file, the searchapi is set to call the backend service available at backend.localhost (either v4, by default, or v3 if specified otherwise by setting BE_VERSION).
For an explanation of how setting BE_VERSION changes the environment creation see here.