A online service that lets you search for SDKs and third party code used by popular apps on the App Store. AppSight lets you pick an app and view all the SDKs used to create it, along with some additional details such as device requirements, requested permissions, URL schemes, and version history. You can also view the data the other way by picking an SDK and viewing a list of the apps that currently use it, along with related SDKs and quick links to the code on Cocoapods, GitHub, Twitter, etc.