📲 Convert Your PWA to an Android App using Bubblewrap

This guide helps you turn a Progressive Web App (PWA) into a fully installable Android app using Bubblewrap. Bubblewrap is a CLI tool from Google that wraps your PWA in a Trusted Web Activity (TWA), making it publishable to the Google Play Store.

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🧱 Prerequisites

Before you begin, make sure you have the following installed:

• ✅ Node.js (v14+) -Terminal prompts sudo apt update sudo apt install nodejs npm -y

• ✅ Java JDK (version 11 or newer) -Terminal prompts sudo apt install openjdk-17-jdk -y

• ✅ Android SDK and adb in PATH (optional, for testing) -Terminal prompts sudo apt install android-sdk -y

• ✅ A PWA with a valid manifest.json hosted publicly

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Validate Your PWA

Ensure your manifest.json contains:

• name, short_name
• start_url
• display: standalone
• icons (at least 192x192 and 512x512)
• theme_color, background_color

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🚀 Installation

1. Install Bubblewrap CLI

npm install -g @bubblewrap/cli

Steps to Convert PWA to Android App

1. Initialize Project Copy the address of manifest.json in your project(web address not the local one) and paste it below instead of that https://yourdomain.com/...

bubblewrap init --manifest https://yourdomain.com/manifest.json

Fill in the required prompts like

App name, package ID (e.g., com.example.myapp)

Start URL

Theme color, background color

Path to your signing key (can generate one)

To generate a key:

keytool -genkey -v -keystore my-release-key.jks -keyalg RSA -keysize 2048 -validity 10000 -alias my-key-alias 📍 Note: keytool comes with Java JDK.

2. Build the APK / AAB

bubblewrap build

You can also build an .aab for Google Play:

bubblewrap build --target aab The output is in the /output/ directory.

🔐 SHA-256 Certificate Fingerprint Setup (for TWA) To enable full-screen Trusted Web Activity (TWA) support, link your Android app with your website using a Digital Asset Link.

Why? The Digital Asset Link is required to enable full-screen Trusted Web Activity (TWA) support. This ensures your APK is verified to open your domain in full-screen mode (without browser UI), using a signed certificate.

🛠 How to Generate If you're using Bubblewrap:

For sha 256 key use the below command here in place of my-key-alias you should type your key-alias keytool -genkey -v -keystore my-release-key.jks -keyalg RSA -keysize 2048 -validity 10000 -alias my-key-alias

If you don’t remember the alias: You can check it by listing all aliases inside the keystore:

keytool -list -keystore ./android/keystore/android.keystore You’ll be asked for the keystore password, and it will show:

Keystore type: JKS Keystore provider: SUN

YourAliasNameHere, Jul 20, 2025, PrivateKeyEntry, Certificate fingerprint (SHA-256): ...

Copy the SHA-256 fingerprint from the output.

🧩 Add to .well-known/assetlinks.json

[ { "relation": ["delegate_permission/common.handle_all_urls"], "target": { "namespace": "android_app", "package_name": "your.package.name", "sha256_cert_fingerprints": [ "YOUR:SHA:256:FINGERPRINT:HERE" <-- here add our sha-256 finger print ] } } ]

Host this file at:

https://yourdomain.com/.well-known/assetlinks.json Now, your app can securely open your PWA in full-screen via TWA.