Passkeys require that you associate a website with your app. To do so, you need to have the associated domain file on your website and the appropriate entitlement in your app.

​

1. Apple App Site Association

• Create a JSON file with at least the following content

{
  "webcredentials": {
    "apps": ["<teamID>.<bundleID>"]
  }
}

• Make the file accessible on your website at the following path

https://<your_domain>/.well-known/apple-app-site-association

Make sure to use your teamID and bundleID in the file hosted on your website.

For more information about supporting associated domains see Apple’s documentation.

​

2. App configuration

Next, update your app.json (or app.config.ts) to include the associatedDomains and deploymentTarget like so:

{
  "expo": {
    "ios": {
      "associatedDomains": ["webcredentials:<your_domain>"]
    }
    "plugins": [
      [
        "expo-build-properties",
        {
          "ios": {
            "deploymentTarget": "17.5"
          }
        }
      ]
    ]
  }
}

​

3. Build

Lastly, build your app!

npx expo prebuild -p ios
npx expo run:ios

To enable passkey support for your Android app, associate your app with a website that your app owns.

​

1. Digital Asset Links

• Create a JSON file with at least the following content

[
  {
    "relation": ["delegate_permission/common.handle_all_urls"],
    "target": {
      "namespace": "android_app",
      "package_name": "<package_name>",
      "sha256_cert_fingerprints": ["<sha256_cert_fingerprint>"]
    }
  }
]

• Make the file accessible on your website at the following path

https://<your_domain>/.well-known/assetlinks.json

Make sure to use your package_name and sha256_cert_fingerprint in the file hosted on your website.

For more information on obtaining the sha256_cert_fingerprint for your app, see the signing report documentation. For more information about generally supporting Digital Asset Links see Google’s documentation.

​

2. Dashboard

You will also need to add your sha256_cert_fingerprint to the allowed Android key hashes list in the Settings tab of the Privy dashboard.

​

3. App configuration

Next, update your app.json (or app.config.ts) to look like:

{
  "expo": {
    "plugins": [
      [
        "expo-build-properties",
        {
          "android": {
            "compileSdkVersion": 34
          }
        }
      ]
    ]
  }
}

​

4. Build

Lastly, build your app!

npx expo prebuild -p android
npx expo run:android