What exact filtering criteria do you want to use? Many are listed in the API docs.
It is not possible to list all patients, so you need to specify one of the
identifier parameters. If you do that, then the
startIndex parameters will work. For example, the following is successful:
curl -u admin:Admin123 -X GET --header 'Accept: application/json' \
Edit: As far as I’m aware, patients are not associated with locations, so I don’t think you’ll be able to filter on that.