linking

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Android App Links require intentFilters with autoVerify in app config

To configure Android App Links, you must add the `android.intentFilters` property to your app config and set the `autoVerify` attribute to `true` on each intent filter. The `autoVerify` property is required for Android App Links to work correctly.

Example intentFilters app config for Android App Links

```json { "expo": { "android": { "intentFilters": [ { "action": "VIEW", "autoVerify": true, "data": [ { "scheme": "https", "host": "*.webapp.io", "pathPrefix": "/records" } ], "category": ["BROWSABLE", "DEFAULT"] } ] } } } ``` This configuration enables the app to appear in the standard Android dialog as an option for handling links to the `webapp.io` domain using the `https` scheme.

Android App Links require two-way association between website and app

To enable Android App Links, you must set up two-way association: website verification requires creating and hosting an `assetlinks.json` file at `/.well-known/assetlinks.json` on your website; native app verification requires code signing that references the target website domain.

assetlinks.json file location for Expo Router websites

For websites built with Expo Router or modern React frameworks like Remix and Next.js, create the `assetlinks.json` file at `public/.well-known/assetlinks.json`. For legacy Expo webpack projects, create it at `web/.well-known/assetlinks.json`.

Example assetlinks.json structure for Android App Links

```json [ { "relation": ["delegate_permission/common.handle_all_urls"], "target": { "namespace": "android_app", "package_name": "com.example", "sha256_cert_fingerprints": [ "14:6D:E9:83:51:7F:66:01:84:93:4F:2F:5E:E0:8F:3A:D6:F4:CA:41:1A:CF:45:BF:8D:10:76:76:CD" ] } } ] ``` The `package_name` should be taken from `android.package` in your app config. The `sha256_cert_fingerprints` array can contain multiple fingerprints to support different variants of your app.

Get SHA256 certificate fingerprint from EAS Build

If using EAS Build to build your Android app, run the command `eas credentials -p android` and select the build profile to view the SHA256 Fingerprint value.

Get SHA256 certificate fingerprint from Google Play Console

If not using EAS to manage code signing, you can find the SHA256 certificate fingerprint in Google Play Console by navigating to Release > Setup > App Signing. The Digital Asset Links JSON snippet displays the fingerprint value in the format `14:6D:E9:83...`.

assetlinks.json hosting requirements

The `assetlinks.json` file must be hosted using a web server, served with content-type `application/json`, and accessible over an HTTPS connection. You can verify the file is accessible by typing the complete URL in a browser's address bar.

Test Android App Links during development with Expo CLI tunnel

You can test Android App Links without deploying a website by using the `--tunnel` flag with Expo CLI. Set the environment variable `EXPO_TUNNEL_SUBDOMAIN=my-custom-domain` to maintain a consistent tunnel URL across dev server restarts, then update the `host` value in `intentFilters` to use the Ngrok URL format `my-custom-domain.ngrok.io`.

Commands for testing Android App Links with tunnel

Start the dev server with: `npx expo start --tunnel` (npm), `yarn expo start --tunnel` (yarn), `pnpm expo start --tunnel` (pnpm), or `bun expo start --tunnel` (bun). Compile the development build with: `npx expo run:android` (npm), `yarn expo run:android` (yarn), `pnpm expo run:android` (pnpm), or `bun expo run:android` (bun). Test with adb: `adb shell am start -a android.intent.action.VIEW -c android.intent.category.BROWSABLE -d "https://my-custom-domain.ngrok.io/" <your-package-name>`

Android App Links verification delay

Android verification may take 20 seconds or longer to take effect, so wait until the verification is complete before testing.

Rebuild app after updating web files for Android App Links

If you update your web files, rebuild the native app to trigger a server update on the vendor side (Google).

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