Android App Links

Android App Links let your app open directly from web URLs — no disambiguation dialog asking which app to use. When configured correctly, tapping a link opens your app instantly.

What you'll learn

• How Android App Links differ from deep links
• Configuring your Digital Asset Links file
• Verifying your app links configuration

Deep links vs. App Links

Android has multiple ways to handle links:

Standard deep links (URL schemes)

yourapp://product/123

• Custom scheme, not a real website
• Shows "Open with..." dialog if multiple apps register
• Can be hijacked by malicious apps

Android App Links

https://yoursite.com/product/123

• Standard HTTPS URLs
• Opens your app directly, no dialog
• Verified ownership prevents hijacking

How verification works

1. App declares intent — Your app's manifest lists URLs it handles
2. assetlinks.json hosted — Your domain serves a Digital Asset Links file
3. Google verifies — At install time, Android checks the file matches your app
4. Links work seamlessly — Verified links open your app directly

The Digital Asset Links file

The DAL file proves you own the domain. It lives at:

https://yourdomain.com/.well-known/assetlinks.json

Example assetlinks.json:

[{
  "relation": ["delegate_permission/common.handle_all_urls"],
  "target": {
    "namespace": "android_app",
    "package_name": "com.yourcompany.app",
    "sha256_cert_fingerprints": [
      "AA:BB:CC:DD:EE:FF:00:11:22:33:44:55:66:77:88:99:AA:BB:CC:DD:EE:FF:00:11:22:33:44:55:66:77:88:99"
    ]
  }
}]

Key fields

ULink handles assetlinks.json for you

When you configure your Android app in ULink:

1. Enter your Package Name and SHA-256 fingerprint
2. ULink automatically generates and serves the DAL file
3. Your custom domain (or ulink.to) is ready for App Links

Getting your SHA-256 fingerprint

From debug keystore

keytool -list -v -keystore ~/.android/debug.keystore -alias androiddebugkey -storepass android -keypass android

From release keystore

keytool -list -v -keystore your-release-key.keystore -alias your-alias

From Google Play Console

Go to Release → Setup → App signing → App signing key certificate → SHA-256

App-side configuration

1. Update AndroidManifest.xml

Add intent filters to your main Activity:

<activity android:name=".MainActivity">
    <intent-filter android:autoVerify="true">
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.DEFAULT" />
        <category android:name="android.intent.category.BROWSABLE" />
        <data
            android:scheme="https"
            android:host="yourdomain.com"
            android:pathPrefix="/" />
    </intent-filter>
</activity>

The android:autoVerify="true" attribute triggers the verification process.

2. Handle incoming links

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)

    val uri = intent?.data
    if (uri != null) {
        handleDeepLink(uri)
    }
}

override fun onNewIntent(intent: Intent?) {
    super.onNewIntent(intent)
    intent?.data?.let { handleDeepLink(it) }
}

Testing App Links

Verify the assetlinks.json

curl https://yourdomain.com/.well-known/assetlinks.json

Use Google's verification tool

Visit: https://developers.google.com/digital-asset-links/tools/generator

Enter your domain and package name to check if verification will succeed.

Test with adb

adb shell am start -a android.intent.action.VIEW \
    -c android.intent.category.BROWSABLE \
    -d "https://yourdomain.com/test"

Check verification status

adb shell pm get-app-links com.yourcompany.app

Look for verified status for your domain.

Troubleshooting

"Open with..." dialog still appears

• Verification may not have completed — uninstall and reinstall the app
• Check that android:autoVerify="true" is set
• Ensure assetlinks.json is served over HTTPS with no redirects

Verification fails

• SHA-256 fingerprint mismatch — double-check the fingerprint
• assetlinks.json not accessible — verify the URL returns 200
• Multiple fingerprints needed — add both debug and release fingerprints

Works on some devices, not others

• Some OEMs modify default browser behavior
• Older Android versions (pre-6.0) don't support App Links
• Check that the user hasn't disabled the app as a default handler

Quick recap

• Android App Links provide verified, seamless deep linking
• ULink automatically generates and serves your assetlinks.json
• Add autoVerify="true" to your intent filter
• Include SHA-256 fingerprints for both debug and release builds
• Test with adb and Google's verification tool