Auth0 provides an Android and iOS SDK to simplify the process of implementing Auth0 authentication in .NET Android and iOS applications.

Use the NuGet Package Manager (Tools -> Library Package Manager -> Package Manager Console) to install the Auth0.OidcClient.AndroidX or Auth0.OidcClient.iOS package, depending on whether you are building an Android or iOS application.

Alternatively, you can use the Nuget Package Manager Console (Install-Package) or the dotnet CLI (dotnet add).

Install-Package Auth0.OidcClient.AndroidX
Install-Package Auth0.OidcClient.iOS

dotnet add Auth0.OidcClient.AndroidX
dotnet add Auth0.OidcClient.iOS

To integrate Auth0 into your application, instantiate an instance of the Auth0Client class, passing an instance of Auth0ClientOptions that contains your Auth0 Domain and Client ID.

using Auth0.OidcClient;

var client = new Auth0Client(new Auth0ClientOptions
{
    Domain = "{yourDomain}",
    ClientId = "{yourDomain}"
}, this);

By default, the SDK will leverage Chrome Custom Tabs for Android and ASWebAuthenticationSession for iOS.

After a user successfully authenticates, they will be redirected to the callback URL you set up earlier in this quickstart.

To handle the callback on Android devices, you need to register an intent that handles this callback URL. An easy way to do this is to register the intent on the same activity from which you called the LoginAsync method to instantiate the authentication flow.

Ensure to replace YOUR_ANDROID_PACKAGE_NAME in the code sample with the actual Package Name for your application, such as com.mycompany.myapplication, and ensure that all the text for the DataScheme, DataHost, and DataPathPrefix is in lower case. Also, set LaunchMode = LaunchMode.SingleTask for the Activity, otherwise the system will create a new instance of the activity every time the Callback URL gets called.

Additionally, you need to handle the intent in the OnNewIntent event in your Activity class. You need to notify the Auth0 OIDC Client to finish the authentication flow by calling the Send method of the ActivityMediator singleton, passing along the URL that was sent in.

After a user successfully authenticates, they will be redirected to the callback URL you set up earlier in this quickstart.

To handle the callback on iOS devices:

• Open your application's Info.plist file in Visual Studio, and go to the Advanced tab.
• Under URL Types, click the Add URL Type button
• Set the Identifier as Auth0, the URL Schemes the same as your application's Bundle Identifier, and the Role as None

This is an example of the XML representation of your info.plist file after you have added the URL Type:

<key>CFBundleURLTypes</key>
<array>
    <dict>
        <key>CFBundleTypeRole</key>
        <string>None</string>
        <key>CFBundleURLName</key>
        <string>Auth0</string>
        <key>CFBundleURLSchemes</key>
        <array>
            <string>YOUR_BUNDLE_IDENTIFIER</string>
        </array>
    </dict>
</array>

Additionally, you need to handle the Callback URL in the OpenUrl event in your AppDelegate class. You need to notify the Auth0 OIDC Client to finish the authentication flow by calling the Send method of the ActivityMediator singleton, passing along the URL that was sent in.

Now that you have configured your Auth0 Application and the Auth0 SDK, you need to set up login for your project. To do this, you will use the SDK’s LoginAsync() method to create a login button that redirects users to the Auth0 Universal Login page.

var loginResult = await client.LoginAsync();

If there isn't any error, you can access the User, IdentityToken, AccessToken and RefreshToken on the LoginResult returned from LoginAsync().

Users who log in to your project will also need a way to log out. Create a logout button using the SDK’s LogoutAsync() method. When users log out, they will be redirected to your Auth0 logout endpoint, which will then immediately redirect them back to the logout URL you set up earlier in this quickstart.

await client.LogoutAsync();

Now that your users can log in and log out, you will likely want to be able to retrieve the profile information associated with authenticated users. For example, you may want to be able to display a logged-in user’s name or profile picture in your project.

The Auth0 SDK for Android and iOS provides user information through the LoginResult.User property.

if (loginResult.IsError == false)
{
    var user = loginResult.User;
    var name = user.FindFirst(c => c.Type == "name")?.Value;
    var email = user.FindFirst(c => c.Type == "email")?.Value;
    var picture = user.FindFirst(c => c.Type == "picture")?.Value;
}