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This guide demonstrates how to use Authsignal’s SDKs together with Cognito to achieve a sign-in UX similar to the Uber mobile app.

Building a mobile sign-in UX inspired by the Uber app

The example uses the Authsignal React Native SDK but a similar example could also be built using our SDKs for iOS, Android, or Flutter.

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Github example code

Cognito lambdas

React Native mobile app

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Authentication methods

Our example app uses Authsignal SDKs together with Cognito to rapidly implement five different authentication methods:
  • SMS OTP (or WhatsApp OTP)
  • Email OTP
  • Passkey
  • Sign in with Apple
  • Sign in with Google
All of these authentication methods are validated in our verify auth challenge response lambda with a minimal amount of code: 
export const handler = async (event) => {
  // For SMS, email OTP, and passkey this will be an Authsignal token
  // For Apple and Google sign-in it will be an Apple or Google ID token
  const token = event.request.challengeAnswer;

  const { isValid } = await authsignal.validateChallenge({
    action: "cognitoAuth",
    userId: event.userName,
    token,
  });

  event.response.answerCorrect = isValid;

  return event;
};

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SMS

SMS OTP is the first authentication method which we present on the sign-in screen.

Signing in with SMS OTP

If the user opts to use SMS and it’s their first time signing in, we also prompt them to:
  • Input their email address after signing in
  • Verify their email address via another OTP challenge
  • Input their first and last name
We verify the email using Authsignal’s SDKs, sharing the same UI implementation for signing in with email OTP.

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Email OTP

Email OTP is an additional authentication method which the user can choose to sign in with.

Signing in with email OTP

If the user chooses this option and it’s their first time signing in, we also prompt them to:
  • Input their phone number after signing in
  • Verify their phone number via another OTP challenge
  • Input their first and last name
We verify the phone number using Authsignal’s SDKs, sharing the same UI implementation for signing in with SMS OTP.

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Passkey

In our example app, a passkey can only be created after both phone number and email have been verified.

Prompting the user to create a passkey after signing in

Once a passkey has been created the user can authenticate with it directly from the sign-in screen.

Signing in with passkey

Following the approach taken by the Uber app, we present the passkey prompt automatically when the sign-in screen appears if a passkey is available on the device. In addition, we add a small passkey icon inside the phone number input which the user can press at any time to make the passkey prompt reappear.

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Apple sign-in

Signing in with Apple is another authentication option which the user can choose.

Signing in with Apple

To implement this we use the react-native-apple-authentication library to obtain an Apple ID token. 
const appleAuthResponse = await appleAuth.performRequest({
  requestedOperation: appleAuth.Operation.LOGIN,
  requestedScopes: [appleAuth.Scope.FULL_NAME, appleAuth.Scope.EMAIL],
});

const idToken = appleAuthResponse.identityToken;
Then we send this ID token to Cognito as the challenge answer and use the Authsignal Server SDK to validate it within our verify auth challenge response lambda.

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Google sign-in

Signing in with Google is the final authentication method which the user can select on our sign-in screen.

Signing in with Google

To implement this we use the react-native-app-auth library to launch a web-based OIDC flow and obtain a Google ID token. 
const config = {
  issuer: "https://accounts.google.com",
  clientId: `${GOOGLE_OAUTH_APP_GUID}.apps.googleusercontent.com`,
  redirectUrl: `com.googleusercontent.apps.${GOOGLE_OAUTH_APP_GUID}:/oauth2redirect/google`,
  scopes: ["openid", "profile", "email"],
};

const authorizeResult = await authorize(config);

const idToken = authorizeResult.idToken;
Then we follow the same approach as for Apple sign-in, sending this ID token to Cognito as the challenge answer and using the Authsignal Server SDK to validate it within our verify auth challenge response lambda.
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