Hey @astar happy to help with this! For the auth verification endpoint all you need to put in is any endpoint from the REST API that will return a status 200 if a user IS authenticated and a non-200 status code if the user is NOT authenticated.
As stated in our docs:
The "auth verification endpoint" is used to test whether or not the user is currently authenticated. Retool will make a GET request to the URL and if the response is not a 20x, it will pop a modal open and ask the user to authenticate against the API.
You can read more about this in our docs here. Hope this helps!