An Application Placement Identifier (APID) is a unique identifier we assign to each ad placement within your applications or mobile websites. Each ad request sent to Millennial Media should contain a placement level APID so we can identify the application or mobile site making the request and improve our system reporting over time.
Does my application or site need many APIDs or just one APID?
Each ad placement in your application or on your mobile website should have its own APID. This provides you the flexibility to better manage and control each placement within your application or site.
Where can I find my APIDs?
You can find APIDs for your applications and mobile websites on the “Apps & Sites” tab.