Reporting data for Email Campaigns is fully available through the API and in two different formats (data is the same, just how it is accessed is slightly different). Here is the overview on that:
Data based on per Contact information, such as which Campaigns a specific Contact opened, bounced, links they clicked. You can find the documentation for that here.
Data based on per Email Campaign basis. This includes a full send list of all Contacts, all opens, all bounces and all clicks for a specific campaign. You can find the documentation for that here.