Android is a software stack for mobile devices, built on the Linux kernel, that Google and a group of partners introduced publicly in 2007. It was announced on November 5, 2007, by the Open Handset Alliance, a consortium of 34 companies led by Google, T-Mobile, HTC, Qualcomm, and Motorola. The press release described Android as “the first truly open and comprehensive platform for mobile devices,” comprising “an operating system, user-interface and applications,” and said it would be released “under one of the most progressive, developer-friendly open-source licenses.”
The platform traces back to Android Inc., a startup that Google had quietly acquired in 2005. The same engineers continued the work inside Google, and the 2007 unveiling was the first public confirmation of what Google had been building. The first Android-powered phone, the T-Mobile G1 (HTC Dream), reached users in 2008, alongside the Android Market application store, exactly within the window the alliance had promised when it said “consumers should expect the first phones based on Android to be available in the second half of 2008.”
Architecturally, Android pairs a Linux kernel with a managed runtime. Early Android applications were written in Java, compiled to Java bytecode, then translated into the compact DEX (Dalvik Executable) format and run on the Dalvik virtual machine, a register-based VM designed for memory-constrained devices. The Android Open Source Project (AOSP) documentation describes Android as “intentionally and explicitly an open source effort” and “a full, production-quality developer product with source code open for customization and porting,” letting manufacturers “create custom variants of the Android OS” for their own hardware.
That open-source model is central to how Android spread. Because device makers could take the AOSP source, adapt it, and ship it without paying a per-device OS license, Android became the default platform for a vast range of phones and tablets from many different vendors. The combination of a free, portable base, a Java-based developer ecosystem, and Google’s own services drove Android to become the most-used operating system in the world, the mobile counterpart to the desktop dominance that earlier operating systems had enjoyed.
Over time the runtime evolved: the Dalvik VM was eventually replaced by ART (the Android Runtime), and the toolchain shifted to a dedicated IDE, Android Studio, with Kotlin joining and later overtaking Java as the recommended application language. But the founding shape laid out in 2007, a Linux base, an open-source platform, and an app marketplace, remained the structure on which the entire Android ecosystem was built.