I'm going to be grabbing the daily report data using the API and would like to know what's the earliest date data is available for and is it the same date for all sites (assuming they existed on that date)?
Also, in the next release of the API can you expand on the JSON error responses. Perhaps with status codes and more meaningful messages.
A request for daily reports for a date range that isn't available returns a generic message:
"Report Request Invalid. Please ensure all parameters are valid in line with API documentation."
Perhaps following http://jsonapi.org/ and for this example saying
message: "Daily report date range not available"