GTS Google: The key to GMS certification

The Android Open Source Project (AOSP) is open to anyone interested in the mobile OS, offering user experience benefits and the ability to run a wide range of apps, including flexibility for hardware requirements.

Devices built this way lack Google's intended Android experience, missing apps and services provided under the Google Mobile Services license — Play Store, Gmail, etc.

This article explores Google's Service certification, Google GTS, the Android GTS test suites' role in ensuring that devices meet Google’s quality standards. Plus, it explains the difference between Android CTS, GTS, VTS, and if adhering to Google GTS standards is necessary at any cost.

Overview: What is Google GTS?

GMS Test Suite by Google (GTS Google) is an automated test suite that is part of the Google Mobile Services (GMS) certification process for Android devices. Passing GTS is mandatory for devices to be certified to run proprietary Google apps.

Purpose and function of GTS Android

The general idea behind all of Google's test suites (there are several) is the compatibility of all built Android devices with the ecosystem. Android GTS test suite is especially focused on verifying if GMS apps developed by Google can run on newly built Android devices.

Apps and services provided by Google

Assuming the whole GTS Google testing and verification process went well, what is included in Google's proprietary services?

Examples of apps provided after passing GMS testing:

• Play Store
• Gmail
• YouTube
• Maps
• Drive
• Chrome

Besides apps, the GMS package includes essential Software Development Kits (SDKs) and APIs for creating compatible GTS Android apps.

• Google Play Services — the GMS core framework that supports SDKs and APIs with features like authentication and location updates while providing updates.
• Firebase Cloud Messaging (FCM) — SDK for Google Push Service used to send and receive app notifications.
• Google Cast — API that offers content streaming to Chromecast and other devices, initiating multiscreen experiences.

Find a full list of Google's products here. Scroll down!

xTS: Google GTS, CTS, VTS, GMS Test Suite

Before exploring the GTS Google certification process, let's clarify the differences between the testing suites provided by Google - the xTS test suites.

For this reason, Google introduced the test suites:

• Android CTS—The Compatibility Test Suite assures device manufacturers that their devices are compatible with the Android platform.
• Android VTS—The Vendor Test Suite focuses on testing the lower-level components of the system like the Android kernel and HAL.
• Android GTS—The GMS Test Suite verifies whether Android devices meet the basic requirements to obtain a GMS license.
• Android STS—The Security Test Suite ensures that Android devices have properly implemented security patches and are protected against known vulnerabilities.

Google GTS CTS are the two xTS test suites we'll focus on since they are essential for GMS certification.

How to use Android GTS to get a Google GTS certificate

Android device certification is called the Android Compatibility program. It requires creating an AOSP ROM that runs on a selected or developed device. VTS tests might have been used to ensure the customized code works on the intended hardware including cameras, Wi-Fi chips, and other components.

The first step in verifying a device's readiness to run the Android OS and third-party apps is implementing all the requirements outlined in Google's compatibility definition document (CDD). The document is kept up-to-date for all released Android versions. Currently, the latest CDD version features Android 15.

Android 15 CDD example

Handheld device implementations that include support for Bluetooth LE: [7.4.3/H-SR-1] Are STRONGLY RECOMMENDED to support Bluetooth LE Data Packet Length Extension.

The second step is verifying CDD adherence using the free Android compatibility test suite (CTS), downloadable as a binary or source code within AOSP.

After confirming compatibility, GTS Google is the next and last checkpoint. Google GTS tests factors such as app compatibility, API implementation, performance, and security to ensure reliability and user experience.

GTS Google is very restrictive on sharing actual details, we barely know anything about the testing scope of GTS in Android. To do the actual tests and get a license, an inquiry needs to be sent to the GMS contact form. This is where the official GTS Google documentation ends.

Google requests information, such as predicted device production numbers, to assess whether to consider the request.

Benefits and issues during Android GTS testing

GTS Google testing is necessary for Android-based consumer devices that rely on existing apps especially when users expect proprietary Google apps; lacking them is a disadvantage. By supporting the customization of Android via apps, manufacturers offer devices for a wide range of user preferences. Plus, the growing app library, enhances device value without in-house development or app-specific issue management.

But, not all Android devices are highly customizable consumer devices. On devices focused on a single task or a limited set of tasks, few apps are needed and passing GTS Google is entirely unnecessary, especially if only custom apps are installed. Even if a broader set of apps is needed, certification is optional, sometimes not even possible to acquire due to hardware requirements that are hard to fulfill if building on custom or off-the-shelf industrial boards.

This simplifies development, especially for smaller vendors (small compared to huge companies like Samsung) since it is hard for them to obtain certification simply based on their production volume.

By the way, solutions such as FCM have alternatives for professional and industrial applications too.

Learn more about GMS vs. Non-GMS in our blog or contact us.

Final thoughts on GTS Google

However practical and great Google services are for highly adaptable consumer devices, specialized devices don't need Google GTS and it’s services. Do not consider GTS Google testing as a must simply because you are building an Android device. Always consider if certification is needed. If you're developing Android-based devices and need expert guidance on GMS and Google GTS alternatives, emteria can help.

Tap into our expertise in creating Google-free customized AOSP solutions.