Learn how the pieces fit together, from the kernel to the HALs to updatable system components.
Find out how the Android security program works and learn how to implement the latest features.
Offer consistent experiences across different Android-powered devices for users and app developers.

Android is an open source operating system for mobile devices and a corresponding open source project led by Google. This site and the Android Open Source Project (AOSP) repository offer the information and source code needed to create custom variants of the Android OS, port devices and accessories to the Android platform, and ensure devices meet the compatibility requirements that keep the Android ecosystem a healthy and stable environment for millions of users.

As an open source project, Android's goal is to avoid any central point of failure in which one industry player can restrict or control the innovations of any other player. To that end, Android is a full, production-quality operating system for consumer products, complete with customizable source code that can be ported to nearly any device and public documentation that is available to everyone (in English at source.android.com and in Simplified Chinese at source.android.google.cn).

Just as you can contribute code to AOSP, you can also contribute to AOSP documentation—and we want your input! Android's flexibility and ever-changing codebase means this site needs your feedback to keep content fresh, accurate, and relevant to Android implementors. We encourage you to check the changelog for details on recent AOSP updates and to report bugs or offer suggestions using the Site Feedback at the bottom of every page (or by visiting g.co/androidsourceissue).

The Generic Kernel Image (GKI) project addresses kernel fragmentation by unifying the core kernel and moving SoC and board support out of the core kernel into loadable vendor modules. GKI also presents a stable Kernel Module Interface (KMI) for vendor modules, so modules and kernel can be updated independently.

Get up-to-date, detailed information and tips on optimizing the Generic Kernel Image (GKI) for your implementation.

Security and Update Bulletins

Every month, we publish the Android Security Bulletin along with the Android Automotive Bulletin and Pixel Update Bulletin.

Go to any of the following Android and Pixel Bulletins to see links to the fixes and new build numbers associated with the latest security release.


Search all available AOSP and developer documents using our experimental tool.
Android 14 is available! This site includes documentation for implementing the features, improvements, and enhancements in the newest version of Android.
Check the latest Android and Pixel Bulletins with links to associated fixes and new build numbers to support the monthly security release.
The build fingerprint is a unique, human-readable string containing manufacturer information issued to each build that is useful in reporting issues and now documented more fully.