This API is used internally by Mixmax's Report Builder UI. It's quite flexible with many different parameters. We suggest learning about its capabilities by inspecting how our Mixmax UI uses it. Open Reports in Chrome, then open Chrome DevTools and click its 'Network' tab. Now create different reports using the Mixmax UI. You'll see Mixmax POST to https://app.mixmax.com/api/reports/data/table?user=X. That's this same API. By watching the parameters that are passed you can get a sense of the parameters you can pass here.