For our new friends:

Logto is an Auth0 alternative designed for modern apps and SaaS products. It offers both Cloud and Open-source services to help you quickly launch your identity and management (IAM) system. Enjoy authentication, authorization, and multi-tenant management all in one.

We recommend starting with a free development tenant on Logto Cloud. This allows you to explore all the features easily.

In this article, we will go through the steps to quickly build the Facebook sign-in experience (user authentication) with iOS (Swift) and Logto.

Prerequisites

• A running Logto instance. Check out the introduction page to get started.
• Basic knowledge of iOS (Swift).
• A usable Facebook account.

Create an application in Logto

Logto is based on OpenID Connect (OIDC) authentication and OAuth 2.0 authorization. It supports federated identity management across multiple applications, commonly called Single Sign-On (SSO).

To create your Native app application, simply follow these steps:

1. Open the Logto Console. In the "Get started" section, click the "View all" link to open the application frameworks list. Alternatively, you can navigate to Logto Console > Applications, and click the "Create application" button.
2. In the opening modal, click the "Native app" section or filter all the available "Native app" frameworks using the quick filter checkboxes on the left. Click the "iOS (Swift)" framework card to start creating your application.
3. Enter the application name, e.g., "Bookstore," and click "Create application".

🎉 Ta-da! You just created your first application in Logto. You'll see a congrats page which includes a detailed integration guide. Follow the guide to see what the experience will be in your application.

Integrate iOS (Swift) SDK

Add Logto SDK as a dependency

Use the following URL to add Logto SDK as a dependency in Swift Package Manager.

https://github.com/logto-io/swift.git

Since Xcode 11, you can directly import a Swift package w/o any additional tool.

We do not support Carthage and CocoaPods at the time due to some technical issues.

Carthage

Carthage needs a xcodeproj file to build, but swift package generate-xcodeproj will report a failure since we are using binary targets for native social plugins. We will try to find a workaround later.

CocoaPods

CocoaPods does not support local dependency and monorepo, thus it's hard to create a .podspec for this repo.

Init LogtoClient

Initialize the client by creating a LogtoClient instance with a LogtoConfig object.

ContentView.swift

import Logto
import LogtoClient

let config = try? LogtoConfig(
  endpoint: "<your-logto-endpoint>", // E.g. http://localhost:3001
  appId: "<your-app-id>"
)
let client = LogtoClient(useConfig: config)

info:

By default, we store credentials like ID Token and Refresh Token in the Keychain. Thus the user doesn't need to sign in again when he returns.

To turn off this behavior, set usingPersistStorage to false:

let config = try? LogtoConfig(
  // ...
  usingPersistStorage: false
)

Sign in

Before we dive into the details, here's a quick overview of the end-user experience. The sign-in process can be simplified as follows:

1. Your app invokes the sign-in method.
2. The user is redirected to the Logto sign-in page. For native apps, the system browser is opened.
3. The user signs in and is redirected back to your app (configured as the redirect URI).

Regarding redirect-based sign-in

1. This authentication process follows the OpenID Connect (OIDC) protocol, and Logto enforces strict security measures to protect user sign-in.
2. If you have multiple apps, you can use the same identity provider (Logto). Once the user signs in to one app, Logto will automatically complete the sign-in process when the user accesses another app.

To learn more about the rationale and benefits of redirect-based sign-in, see Logto sign-in experience explained.

---

Configure redirect URI

Let's switch to the Application details page of Logto Console. Add a Redirect URI io.logto://callback and click "Save changes".

info:

The Redirect URI in iOS SDK is only for internal use. There's NO NEED to add a Custom URL Scheme until a connector asks.

Sign-in and sign-out

note:

Before calling .signInWithBrowser(redirectUri:), make sure you have correctly configured Redirect URI in Admin Console.

You can use client.signInWithBrowser(redirectUri:) to sign in the user and client.signOut() to sign out the user.

For example, in a SwiftUI app:

ContentView.swift

struct ContentView: View {
  @State var isAuthenticated: Bool

  init() {
    isAuthenticated = client.isAuthenticated
  }

  var body: some View {
    VStack {
      if isAuthenticated {
        Button("Sign Out") {
          Task { [self] in
            await client.signOut()
            isAuthenticated = false
          }
        }
      } else {
        Button("Sign In") {
          Task { [self] in
            do {
              try await client.signInWithBrowser(redirectUri: "${
                props.redirectUris[0] ?? 'io.logto://callback'
              }")
              isAuthenticated = true
            } catch let error as LogtoClientErrors.SignIn {
              // error occured during sign in
            } catch {
              // other errors
            }
          }
        }
      }
    }
  }
}

Checkpoint: Test your application

Now, you can test your application:

1. Run your application, you will see the sign-in button.
2. Click the sign-in button, the SDK will init the sign-in process and redirect you to the Logto sign-in page.
3. After you signed in, you will be redirected back to your application and see the sign-out button.
4. Click the sign-out button to clear token storage and sign out.

Add Facebook connector

To enable quick sign-in and improve user conversion, connect with iOS (Swift) as an identity provider. The Logto social connector helps you establish this connection in minutes by allowing several parameter inputs.

To add a social connector, simply follow these steps:

1. Navigate to Console > Connectors > Social Connectors.
2. Click "Add social connector" and select "Facebook".
3. Follow the README guide and complete required fields and customize settings.

note:

If you are following the in-place Connector guide, you can skip the next section.

Set up Facebook login

Register a Facebook developer account

Register as a Facebook Developer if you don't already have one

Set up a Facebook app

1. Visit the Apps page.
2. Click your existing app or create a new one if needed.
   • The selected app type is up to you, but it should have the product Facebook Login.
3. On the app dashboard page, scroll to the "Add a product" section and click the "Set up" button on the "Facebook Login" card.
4. Skip the Facebook Login Quickstart page, and click the sidebar -> "Products" -> "Facebook Login" -> "Settings".
5. In the Facebook Login Settings page, fill ${your_logto_origin}/callback/${connector_id} in the "Valid OAuth Redirect URIs" field. The connector_id can be found on the top bar of the Logto Admin Console connector details page. E.g.:
   • https://logto.dev/callback/${connector_id} for production
   • https://localhost:3001/callback/${connector_id} for testing in the local environment
6. Click the "Save changes" button at the bottom right corner.

Compose the connector JSON

1. In the Facebook app dashboard page, click the sidebar -> "Settings" -> "Basic".
2. You will see the "App ID" and "App secret" on the panel.
3. Click the "Show" button following the App secret input box to copy its content.
4. Fill out the Logto connector settings:
   • Fill out the clientId field with the string from App ID.
   • Fill out the clientSecret field with the string from App secret.
   • Fill out the scope field with a comma or space separated list of permissions in string. If you do not specify a scope, the default scope is email,public_profile.

Test sign-in with Facebook's test users

You can use the accounts of the test, developer, and admin users to test sign-in with the related app under both development and live app modes.

You can also take the app live directly so that any Facebook user can sign in with the app.

• In the app dashboard page, click the sidebar -> "Roles" -> "Test Users".
• Click the "Create test users" button to create a testing user.
• Click the "Options" button of the existing test user, and you will see more operations, e.g., "Change name and password".

Publish Facebook sign-in settings

Usually, only the test, admin, and developer users can sign in with the related app under development mode.

To enable normal Facebook users sign-in with the app in the production environment, you maybe need to switch your Facebook app to live mode, depending on the app type. E.g., the pure business type app doesn't have the "live" switch button, but it won't block your use.

1. In the Facebook app dashboard page, click the sidebar -> "Settings" -> "Basic".
2. Fill out the "Privacy Policy URL" and "User data deletion" fields on the panel if required.
3. Click the "Save changes" button at the bottom right corner.
4. Click the "Live" switch button on the app top bar.

Config types

Name	Type
clientId	string
clientSecret	string
scope	string

Save your configuration

Double check you have filled out necessary values in the Logto connector configuration area. Click "Save and Done" (or "Save changes") and the Facebook connector should be available now.

Enable Facebook connector in Sign-in Experience

Once you create a social connector successfully, you can enable it as a "Continue with Facebook" button in Sign-in Experience.

1. Navigate to Console > Sign-in experience > Sign-up and sign-in.
2. (Optional) Choose "Not applicable" for sign-up identifier if you need social login only.
3. Add configured Facebook connector to the "Social sign-in" section.

Testing and Validation

Return to your iOS (Swift) app. You should now be able to sign in with Facebook. Enjoy!

Further readings

End-user flows: Logto provides a out-of-the-box authentication flows including MFA and enterprise SSO, along with powerful APIs for flexible implementation of account settings, security verification, and multi-tenant experience.

Authorization: Authorization defines the actions a user can do or resources they can access after being authenticated. Explore how to protect your API for native and single-page applications and implement Role-based Access Control (RBAC).

Organizations: Particularly effective in multi-tenant SaaS and B2B apps, the organization feature enable tenant creation, member management, organization-level RBAC, and just-in-time-provisioning.

Customer IAM series Our serial blog posts about Customer (or Consumer) Identity and Access Management, from 101 to advanced topics and beyond.