Android is a mobile operating system based on a modified version of the Linux kernel and other open-source software, designed primarily for touchscreen-based mobile devices such as smartphones and tablets. It is the world's most widely used operating system due to it being used on most smartphones and tablets outside of iPhones and iPads, which use Apple's iOS and iPadOS, respectively. As of October 2024, Android accounts for 45% of the global operating system market, followed by Windows with 26%.
Android has historically been developed by a consortium of developers known as the Open Handset Alliance, but its most widely used version is primarily developed by Google. It was unveiled in November 2007, with the first commercial Android device, the HTC Dream, being launched in September 2008.
At its core, the operating system is known as the Android Open Source Project (AOSP) and is free and open-source software (FOSS) primarily licensed under the Apache License. However, most devices run the proprietary Android version developed by Google, which ships with additional proprietary closed-source software pre-installed, most notably Google Mobile Services (GMS), which includes core apps such as Google Chrome, the digital distribution platform Google Play, and the associated Google Play Services development platform. Firebase Cloud Messaging is used for push notifications. While AOSP is free, the "Android" name and logo are trademarks of Google, which imposes standards to restrict the use of Android branding by "uncertified" devices outside their ecosystem.
Over 70% of smartphones based on the Android Open Source Project run Google's ecosystem (which is known simply as Android), some with vendor-customized user interfaces and software suites, such as TouchWiz and later One UI by Samsung and HTC Sense. Competing ecosystems and forks of AOSP include Fire OS developed by Amazon, ColorOS by Oppo, OriginOS by Vivo, MagicUI by Honor, and custom ROMs such as LineageOS, as well as Meta Horizon OS for VR headsets.
Android's source code has been used to develop variants on a range of other electronics, such as game consoles, digital cameras, portable media players, and PCs, each with a specialized user interface. Some well-known derivatives include Android TV for televisions and Wear OS for wearables, both developed by Google. Software packages on Android, which use the APK format, are generally distributed through proprietary application stores like Google Play Store, Amazon Appstore, Samsung Galaxy Store, Huawei AppGallery, Cafe Bazaar, GetJar, and Aptoide, or open source platforms like F-Droid.
Android has been the most used operating system worldwide on smartphones since 2011 and on tablets since 2013. As of May 2021, it has over three billion monthly active users, the largest installed base of any operating system in the world, and, as of 2024, the Google Play Store features 1.7 million apps; a decline from its of peak of over 3 million apps in April 2021. Android 15, released on October 15, 2024, is the latest version and includes improvements specific to foldable phones, tablets, desktop-sized screens, and Chromebooks.