Google Play Services icon
Google Play Services is a proprietary background service and API package for Android devices. When first introduced in 2012, it provided simple access to the Google+ APIs and OAuth 2.0, but since then it has expanded to cover a large variety of Google's services, allowing applications to easily communicate with the services through common means, being internally referred to as simply GMS. As of January 2014, it has been installed more than one billion times on Android devices.
Google Play Game Services can be used by application developers to allow a more competitive and social experience through the use of leaderboards, both public and between friends, achievements and multiplayer sessions. Saved Games API is available to quickly sync game saves on Google's cloud infrastructure as well. The Location APIs abstract away specifics about the location technologies, providing Geofencing APIs for scheduling specific actions upon the user entering or leaving specific geographic boundaries, Fused Location Provider for acquiring location information with as reduced power usage as possible and activity recognition for allowing applications to adapt to the current action of the user (e.g. cycling, walking, etc.).
The Google+ platform provides single sign-on, allowing the user to be automatically authenticated inside applications providing a more personalized experience, and sharing options using Google+. Google Maps Android API allows applications to include Google Maps or Street View without the need to open a separate application, allowing full control over the camera and providing means of adding custom markers and overlays over the map. Google Drive Android API exposes Google Drive to be used as a storage structure, providing easy lookup and syncing of documents along with various other tools for manipulating the files. Google Cast Android API adds casting functionality to allow Android applications to display content on TVs using Google Cast, additionally providing various helpers for common audio, video and image types.
Google Mobile Ads integrate advertisements into applications, allowing simple monetization by over a million Google advertisers and sophisticated ad targeting based on factors such as user location. Google Wallet Instant Buy allows purchases of services and goods to be done from a Google Wallet, providing a streamlined flow of just a few taps with minimized data entry done by the user. Google Play Services provides other APIs such as the Google Fit API, Google account authentication methods and Google Analytics APIs. Google Play Services is used by almost all Google apps and have system-level powers to provide multiple internal features.
The most common error faced by Android users is "Unfortunately, Google Play services has stopped." which is quite normal and can be fixed by clearing the cache or re-installing the Google Play services.
Google Play Services is automatically updated through Google Play on devices with that application installed that are running Android 4.0 or newer. This means Google can do fast, silent rollouts of updates, providing new functionality to older devices without manufacturers having to update the Android firmware itself, working around the fragmentation of the platform for which it had become infamous.
Android Open Source Project (AOSP) was announced in 2007, and has functioned as the baseline system for all OEMs and firmware modifications such as CyanogenMod. Various apps from AOSP are abandoned, and instead released on Google Play with a closed-source model. Many apps only function with Google Play Services available (such as many of the Google apps like Gmail, YouTube and Google Maps).
Any party interested in distributing Google Play Services as a part of the Google apps package must acquire a license from Google, which often results in a contractual agreement locking the manufacturer into Android. Additionally, enthusiasts who are not able to or are not interested in signing such an agreement, but are interested in modifying the Android system are required to either opt-out of Google Play Services or for obtaining the Google apps package either from a device which has them pre-installed or an unofficial source. Google Play Services can be found in the Google Play Store, demanding 80 permissions . The store only works when the Google Play Services are already running.