Publishing a Trusted Web Activity on the Amazon Appstore

While the Google Play Store is the primary destination for Android applications, developers looking to maximise their reach should look toward alternative marketplaces. The Amazon Appstore is the second-largest Android app ecosystem, serving as the official marketplace for millions of Fire tablets, Fire TV devices, and Windows 11 devices via the Windows Subsystem for Android. Because Fire OS is a fork of the Android Open Source Project (AOSP), applications packaged as Trusted Web Activities (TWAs) can run successfully on Amazon hardware.

However, publishing a TWA to the Amazon Appstore involves a unique set of technical constraints. Unlike standard Android devices that ship with Google Chrome and Google Mobile Services (GMS), Amazon devices run Amazon's proprietary browser, Silk, and rely on Amazon Mobile Services. Understanding how to adapt your TWA for this environment is essential for a successful release.

The Browser Engine on Fire OS Devices

A Trusted Web Activity requires a compatible Custom Tabs provider to render the web content. On standard Android devices, this provider is typically Google Chrome. If Google Chrome is not present, the TWA wrapper searches for other installed browsers that support the Custom Tabs protocol.

On Amazon Fire OS devices, Google Chrome is not pre-installed, and the Google Play Store is absent. Instead, these devices ship with the Amazon Silk Browser. Fortunately, modern versions of the Silk Browser are built on the Chromium open-source project and fully support the Custom Tabs specification. When your signed TWA APK is launched on a Fire tablet, the wrapper detects the Silk Browser and uses it to render your PWA seamlessly, providing the same performance benefits and modern web API access that you expect under Chrome.

Digital Asset Links on Amazon Fire OS

To remove the browser address bar from your application and display your PWA in full-screen standalone mode, you must verify ownership of your domain using Digital Asset Links. This process remains mandatory when publishing on the Amazon Appstore, but the execution differs from the standard Google Play workflow.

When you submit an APK to the Amazon Appstore, Amazon offers an app signing service similar to Google Play App Signing. If you choose to let Amazon manage your app signing keys, Amazon will resign your APK with a unique Amazon developer key before distributing it to customers. This means the SHA-256 certificate fingerprint of the APK installed on user devices will not match the signature of the APK you originally uploaded.

To ensure the URL bar is removed on Fire OS devices, you must retrieve the public SHA-256 fingerprint of the Amazon-signed certificate from the Amazon Developer Console. This fingerprint must then be added to your domain's assetlinks.json file alongside your existing Google Play fingerprint. The JSON structure will accommodate multiple signatures easily:

[ { "relation": ["delegate_permission/common.handle_all_urls"], "target": { "namespace": "android_app", "package_name": "com.yourdomain.app", "sha256_cert_fingerprints": [ "GOOGLE_PLAY_SHA256_FINGERPRINT", "AMAZON_APPSTORE_SHA256_FINGERPRINT" ] } } ]

Failing to include the Amazon-specific fingerprint will result in your application displaying a URL bar at the top of the screen when run on Fire tablets, undermining the native look and feel of your application.

Step-by-Step Submission Process

Publishing your TWA on the Amazon Appstore involves preparing your asset package, setting up your developer portal, and configuring your targeting settings. The process can be completed using the following steps:

1. Generate Your Signed APK or AAB

Using your preferred TWA generation tool, compile your progressive web app into a signed release APK or Android App Bundle (AAB). Ensure that your package name is identical to the one used on Google Play to simplify domain verification and maintain brand consistency.

2. Create an Amazon Developer Account

Register for a developer account at the Amazon Developer Portal. Registration is free and does not require the annual fees associated with some other major application storefronts.

3. Add a New App

Navigate to the App Console, click on Add a New App, and select Android. Fill in your application metadata, including the title, category, and default language.

4. Upload the App Binary

Upload your signed APK or AAB to the App Files section. Amazon will automatically parse the file to detect the package name, minimum SDK requirements, and target hardware platforms.

5. Configure Device Support

Because Fire OS runs on diverse hardware, you must review the device support list. By default, Amazon enables support for all compatible devices, including Fire tablets and Fire TV. If your web application is not optimised for television interfaces or remote control navigation, manually disable Fire TV support to prevent poor user experiences and subsequent negative reviews.

Comparing Google Play and Amazon Appstore

While both platforms distribute Android binaries, key differences exist in how they manage, verify, and run Trusted Web Activities. The table below outlines these differences:

Common Pitfalls and Troubleshooting

When deploying TWAs to Amazon devices, developers often encounter specific technical hurdles. The most common issue is the persistence of the URL browser bar. If the URL bar does not disappear on your test Fire tablet, double-check that your assetlinks.json file is correctly formatted, accessible over HTTPS, and contains the exact SHA-256 fingerprint provided in the Amazon Appstore console under the App Release section.

Another common pitfall relates to third-party integrations. If your PWA relies on Google Play Services APIs for features like Google Sign-In or Google Play Billing, these APIs will fail on Fire OS devices because Google services are not present. To build a resilient TWA for the Amazon Appstore, ensure your web application degrades gracefully by offering standard web-based alternatives, such as standard OAuth login flows instead of proprietary Google native sign-in buttons.