fabric.io Crashlytics is a service for watching number of daily users, log of crashs and ... . Can I use fabric.io Crashlytics in GPL Android app? If the answer is yes, should I publish the API key with source? Or can I hide it in published source code?
UPDATE: I communicate with this library through a library they provided for us and watch the number of users and crash logs through my dashboard in http://fabric.io. The library is not open source.