It depends. If your API was built underneath your own site, then it's easy. FB's API doesn't seem to actually support anything on the main site, e.g., I doubt

It depends. If your API was built underneath your own site, then it's easy. FB's API doesn't seem to actually support anything on the main site, e.g., I doubt their own "apps" actually run on the FB Apps API. And there's no incentive for any of the engineers to build them like that, because they have such lateral access to internal code and data.