Agent Skill · Android

verified-email

Provides a complete workflow for implementing verified email retrieval on Android Credential Manager API. Use this skill to integrate a secure, OTP-less email verification flow into an Android app. This skill solves the problem of high-friction sign-up processes by leveraging cryptographically verified credentials from trusted providers like Google.

View SKILL.md on GitHub → Source repository Provider profile
Provider: Android Path in repo: identity/verified-email/SKILL.md

Skill body

Fundamentals

Standards \& Examples

Requirements

Use Cases

Email verification is applicable for the following use cases:

Limitations \& Nuances

Scope \& Pre-requisites

Crucial : This skill focuses exclusively on the Android client-side integration . It does not implement the app’s server-side cryptographic validation logic. Server-side validation of the returned credential is required for security and must be implemented in your backend.

Codebase exploration for Use Cases

Get started with the following queries in project source code to find relevant screens with different use cases to implement verified email:

Identifying Integration Points

To implement this feature effectively, you must first locate the relevant flows in your codebase. To initiate, start with the following strategies to cater to different use cases using verified email:

1. Search for Navigation Routes

If your app uses Navigation, search for routes or destinations related to authentication:

Look for:

2. Locate Authentication ViewModels

Find the business logic handling user attributes and account creation, account recovery:

3. Find instances of reauthentication for sensitive actions

For reauthentication use cases, find areas where users perform sensitive actions:

Important pointers for Implementation

This guide describes how to implement verified email retrieval using the Digital Credentials Verifier API through an OpenID for Verifiable Presentations (OpenID4VP) request.

Add dependencies

In your app’s build.gradle file, add the following dependencies for Credential Manager:

Kotlin

dependencies {
    implementation("androidx.credentials:credentials:1.7.0-alpha02")
    implementation("androidx.credentials:credentials-play-services-auth:1.7.0-alpha02")
}

Groovy

dependencies {
    implementation "androidx.credentials:credentials:1.7.0-alpha02"
    implementation "androidx.credentials:credentials-play-services-auth:1.7.0-alpha02"
}

Initialize Credential Manager

Use your app or activity context to create a CredentialManager object.

// Use your app or activity context to instantiate a client instance of
// CredentialManager.
private val credentialManager = CredentialManager.create(context)

Construct the Digital Credential request

To request a verified email, construct a GetCredentialRequest containing a GetDigitalCredentialOption. This option requires a requestJson string formatted as an OpenID for Verifiable Presentations (OpenID4VP) request.

The OpenID4VP request JSON must follow a specific structure. The current providers support a JSON structure with an outer "digital": {"requests": [...]} wrapper.

    val nonce = generateSecureRandomNonce()

    // This request follows the OpenID4VP spec
    val openId4vpRequest = """
{
  "requests": [
    {
      "protocol": "openid4vp-v1-unsigned",
      "data": {
        "response_type": "vp_token",
        "response_mode": "dc_api",
        "nonce": "$nonce",
        "dcql_query": {
          "credentials": [
            {
              "id": "user_info_query",
              "format": "dc+sd-jwt",
               "meta": { 
                  "vct_values": ["UserInfoCredential"] 
               },
              "claims": [ 
                {"path": ["email"]}, 
                {"path": ["name"]},  
                {"path": ["given_name"]},
                {"path": ["family_name"]},
                {"path": ["picture"]},
                {"path": ["hd"]},
                {"path": ["email_verified"]}
              ]
            }
          ]
        }
      }
    }
  ]
}
"""

    val getDigitalCredentialOption = GetDigitalCredentialOption(requestJson = openId4vpRequest)
    val request = GetCredentialRequest(listOf(getDigitalCredentialOption))

The request contains the following key information:

Next, wrap the openId4vpRequest JSON in a GetDigitalCredentialOption, create a GetCredentialRequest, and call getCredential().

Present the request to the user

Present the user with the request, using the Credential Manager built-in UI.

try {
    // Requesting Digital Credential from user...
    val result = credentialManager.getCredential(activity, request)

    when (val credential = result.credential) {
        is DigitalCredential -> {
            val responseJsonString = credential.credentialJson

            // Successfully received digital credential response.

            // Next, parse this response and send it to your server.
            // ...
        }

        else -> {
            // handle Unexpected State() - Up to the developer
        }
    }
} catch (e: Exception) {
    // handle exceptions - Up to the developer
}

[!NOTE] Note: There is no equivalent of Sign in with Google’s preferImmediatelyAvailableCredentials for Digital Credentials. If no verifiable credential is found (for example, no eligible account on device), the user will be shown a “No options available” or similar system screen.

Parse the response on the client

After receiving the response, you can perform a preliminary parse on the client. This is useful for immediately updating the UI, for example, by showing the user’s name.

[!IMPORTANT] Important: This step is not for validation. Full cryptographic verification must be performed on your server.

The following code extracts the raw Selective Disclosure JWT (SD-JWT) and uses a helper to decode its claims.

// 1. Parse the outer JSON wrapper to get the `vp_token`
val responseData = JSONObject(responseJsonString)
val vpToken = responseData.getJSONObject("vp_token")

// 2. Extract the raw SD-JWT string
val credentialId = vpToken.keys().next()
val rawSdJwt = vpToken.getJSONArray(credentialId).getString(0)

// 3. Use your parser to get the verified claims
// Server-side validation/parsing is highly recommended.

// Assumes a local parser like the one in our SdJwtParser.kt sample
val claims = SdJwtParser.parse(rawSdJwt)
Log.d("TAG", "Parsed Claims: ${claims.toString(2)}")

// 4. Create your VerifiedUserInfo object with REAL data
val userInfo = VerifiedUserInfo(
    email = claims.getString("email"),
    displayName = claims.optString("name", claims.getString("email"))
)

Handle the response

The Credential Manager API will return a DigitalCredential response.

The following is an example of what the raw responseJsonString looks like, and what the claims look like after parsing the inner SD-JWT where you get additional metadata as well along with verified email:

/*
// Example of the raw JSON response from credential.credentialJson:
{
  "vp_token": {
    // This key matches the 'id' you set in your dcql_query
    "user_info_query": [
      // The SD-JWT string (Issuer JWT ~ Disclosures ~ Key Binding JWT)
      "eyJhbGciOiJ...~WyI...IiwgImVtYWlsIiwgInVzZXJAZXhhbXBsZS5jb20iXQ~...~eyJhbGciOiJ..."
    ]
  }
}

// Example of the parsed and verified claims from the SD-JWT on your server:
{
  "cnf": {
    "jwk": {..}
  },
  "exp": 1775688222,
  "iat": 1775083422,
  "iss": "https://verifiablecredentials-pa.googleapis.com",
  "vct": "UserInfoCredential",
  "email": "[email protected]",
  "email_verified": true,
  "given_name": "Jane",
  "family_name": "Doe",
  "name": "Jane Doe",
  "picture": "http://example.com/janedoe/me.jpg",
  "hd": ""
}
 */

[!NOTE] Note: We highly recommend that after receiving the verified email, you trigger Credential Manager’s passkey creation.

Server-side validation for account creation

Since the retrieved email is cryptographically verified, you can omit the email OTP verification step, significantly reducing sign-up friction and potentially increasing conversion. This process is best handled on your server. The client sends the raw response (containing the vp_token) and the original nonce to a new server endpoint.

For verification, your application must send the full responseJsonString to your server for cryptographic validation before creating an account or logging the user in.

The digital credential provides two critical levels of verification for your server:

The validation on the server must achieve the following:

[!NOTE] Note: Use a standard library (such as @sd-jwt/sd-jwt-vc for Node.js) to perform the verification steps as outlined in the OpenID for Verifiable Presentations specification.

For full security, make sure that you also validate the nonce to prevent replay attacks.

By combining these steps, your server can validate both the authenticity of the data and the identity of the presenter, ensuring the credential wasn’t intercepted or spoofed before provisioning the new account.

try {
    // Send the raw credential response and the original nonce to your server.
    // Your server must validate the response. createAccountWithVerifiedCredentials
    // is a custom implementation per each RP for server side verification and account creation.
    val serverResponse = createAccountWithVerifiedCredentials(responseJsonString, nonce)

    // Server returns the new account info (e.g., email, name)
    val claims = JSONObject(serverResponse.json)

    val userInfo = VerifiedUserInfo(
        email = claims.getString("email"),
        displayName = claims.optString("name", claims.getString("email"))
    )

    // handle response - Up to the developer
} catch (e: Exception) {
    // handle exceptions - Up to the developer
}

Passkey creation

An optional but highly recommended next step after provisioning an account is to immediately create a passkey for that account. This provides a secure, passwordless method for the user to sign in. This flow is identical to a standard passkey registration.

WebView support

For the flow to work on a WebView, developers should implement a JavaScript bridge (JS Bridge) to facilitate the handoff. This bridge allows the Webview to signal the native app, which can then perform the actual call to the Credential Manager API.

See also

Critical Security Guidelines

To maintain the integrity of the email verification flow, the following security requirements are mandatory:

Skill frontmatter

license: Complete terms in LICENSE.txt metadata: {"author"=>"Google LLC", "last-updated"=>"2026-05-16", "keywords"=>["implementation", "Android", "Credential Manager", "Digital Credentials", "Verified Email", "OpenID4VP", "SD-JWT", "OTP-less", "authentication", "passkeys", "CredMan", "identity."]}