Android's purpose is to establish an open platform for developers to build innovative apps.
- The Android Compatibility program defines technical details of the Android platform and provides tools for OEMs to ensure developer apps run on a variety of devices.
- The Android SDK provides built-in tools for developers to clearly state the device features required by their apps.
- App distribution systems, like Google Play, filter apps so users see only the apps that are compatible with their devices.
Reasons to build compatible Android devices
Users want customizable devices
A mobile phone is a highly personal, always-on, always-present gateway to the Internet. We haven't met a user yet who didn't want to customize it by extending its functionality. That's why Android was designed as a robust platform for running aftermarket apps.
Developers outnumber us all
No device manufacturer can write all the software a user could conceivably need. We need third-party developers to write the apps users want, so the Android Open Source Project (AOSP) aims to make app development as easy and open as possible.
Everyone needs a common ecosystem
Every line of code developers write to work around a bug is a line of code that didn't add a new feature. The more compatible mobile devices are, the more apps we'll have to run on those devices. By building a fully compatible Android device, you benefit from the huge pool of apps written for Android while increasing the incentive for developers to build more apps.
The Android compatibility program works for the benefit of the entire Android community, including users, developers, and device manufacturers.
Each group depends on the others. Users want a wide selection of devices and great apps; great apps come from developers motivated by a large market for their apps with many devices in users' hands; device manufacturers rely on a wide variety of great apps to increase their products' value for consumers.
Our goals were designed to benefit each of these groups:
Provide a consistent app and hardware environment to app developers. Without a strong compatibility standard, devices can vary so greatly that developers must design different versions of their apps for different devices. The compatibility program provides a precise definition of what developers can expect from a compatible device in terms of APIs and capabilities. Developers can use this information to make good design decisions, and be confident that their apps will run well on any compatible device.
Enable a consistent app experience for consumers. If an app runs well on one compatible Android device, it should run well on any other device that is compatible with the same Android platform version. Android devices will differ in hardware and software capabilities, so the compatibility program also provides the tools needed for distribution systems such as Google Play to implement appropriate filtering. This means users see only the apps they can actually run.
Enable device manufacturers to differentiate while being compatible. The Android compatibility program focuses on the aspects of Android relevant to running third-party apps, which allows device manufacturers the flexibility to create unique devices that are nonetheless compatible.
Minimize costs and overhead associated with compatibility. Ensuring compatibility should be easy and inexpensive to device manufacturers. The testing tool is free, open source, and available for download. It is designed to be used for continuous self-testing during the device development process to eliminate the cost of changing your workflow or sending your device to a third party for testing. Meanwhile, there are no required certifications, and thus no corresponding costs and fees.
The Android compatibility program consists of three key components:
- The Android Open Source Project source code
- The Compatibility Definition Document (CDD), representing the "policy" aspect of compatibility
- The Compatibility Test Suite (CTS), representing the "mechanism" of compatibility
Android compatibility is free, and it's easy
To build an Android-compatible mobile device, follow this three-step process:
- Obtain the Android software source code. This is the source code for the Android platform that you port to your hardware.
- Comply with the Android Compatibility Definition Document (CDD) (PDF, HTML). The CDD enumerates the software and hardware requirements of a compatible Android device.
- Pass the Compatibility Test Suite (CTS). Use the CTS as an ongoing aid to evaluate compatibility during the development process.
After complying with the CDD and passing the CTS, your device is Android compatible, meaning Android apps in the ecosystem provide a consistent experience when running on your device.
Just as each version of the Android platform exists in a separate branch in the source code tree, there is a separate CTS and CDD for each version as well. The CDD, CTS, and source code are—along with your hardware and your software customizations—everything you need to create a compatible device.
Licensing Google Mobile Services (GMS)
After building an Android compatible device, consider licensing Google Mobile Services (GMS), Google's proprietary suite of apps (Google Play, YouTube, Google Maps, Gmail, and more) that run on top of Android. GMS is not part of the Android Open Source Project and is available only through a license with Google. For information on how to request a GMS license, see our Contact/Community page.