For a dashboard I want to get some basic information about all cases. e.g get all open cases. I did find some api functionality to gather data by id about a single case.
https://developer.salesforce.com/docs/api-explorer/sobject/Case
Is is possible to receive data about all cases?
/services/data/v39.0/sobjects/Case
However what I observe is that not all fields are retrieved. I think you need to retrieve those records using Data Loader.