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<p>Android's purpose is to establish an open platform for developers to build
innovative apps.</p>
<ul>
<li>The Android Compatibility program defines technical details of the
Android platform and provides tools for OEMs to ensure developer applications
run on a variety of devices.</li>
<li>The Android SDK provides built-in tools for developers to clearly state the
device features required by their applications.</li>
<li>Google Play shows applications only to those devices that can properly run
those applications.</li>
</ul>

<h2 id="why-build-compatible-android-devices">Why build compatible Android
devices?</h2>

<h3 id="users-want-a-customizable-device">Users want customizable devices</h3>

<div class="attempt-right">
  <img src="images/compat-ecosystem.png" alt="Compatibility ecosystem" id="figure1" />
  <p class="img-caption">
    <strong>Figure 1.</strong> The Android ecosystem thrives with device compatibility
  </p>
</div>

<p>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 applications.</p>

<h3 id="developers-outnumber-us-all">Developers outnumber us all</h3>
<p>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 application development as easy
and open as possible.</p>

<h3 id="everyone-needs-a-common-ecosystem">Everyone needs a common ecosystem</h3>
<p>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
applications 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.</p>

<h2 id="android-compatibility-is-free-and-its-easy">Android compatibility is
free, and it's easy</h2>
<p>To build an Android-compatible mobile device, follow this three-step
process:</p>
<ol>
<li><em>Obtain the <a href="/source/index.html">Android software source
code</a></em>. This is the source code for the Android platform that you port
to your hardware.</li>
<li><em>Comply with the Android Compatibility Definition Document (CDD)</em>
(<a href="/compatibility/android-cdd.pdf">PDF</a>, <a
href="/compatibility/android-cdd.html">HTML</a>). The CDD enumerates
the software and hardware requirements of a compatible Android device.</li>
<li><em>Pass the <a href="/compatibility/cts/">Compatibility
Test Suite (CTS)</a></em>. Use the CTS as an ongoing aid to evaluate
compatibility during the development process.</li> </ol>

<p>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. For details about the Android
compatibility program, see the <a href="overview.html">program overview</a>.</p>

<h2 id="licensing-gms">Licensing Google Mobile Services (GMS)</h2>
<p>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
<a href="contact-us.html">Contact Us</a>.</p>

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