Every app needs authentication and authorization. Logto is an Auth0 alternative designed for modern apps and SaaS products.
In this article, we will go through the steps to quickly build the Twilio 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 Twilio account.
Create an application in Logto
In you browser, open a new tab and enter the link of Logto Admin Console.
Once the page is loaded, in the "Get Started" section click the View all
link to open the application framework list page.
Choose your application type
In the opening modal, scroll to 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.
Enter application name
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 Logto 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.
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)
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:
- Your app invokes the sign-in method.
- The user is redirected to the Logto sign-in page. For native apps, the system browser is opened.
- The user signs in and is redirected back to your app (configured as the redirect URI).
Regarding redirect-based sign-in
- This authentication process follows the OpenID Connect (OIDC) protocol, and Logto enforces strict security measures to protect user sign-in.
- 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".
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
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:
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
}
}
}
}
}
}
}
Open your iOS app to test if the integration works. When you click the "Sign In" button, the page should be redirected to a Logto sign-in page, and you should be able to create a new account by entering username and password and complete the sign-in process.
Add Twilio connector
To add or change SMS connector, go to the "Connector" tab in the Admin Console, then click on "Email and SMS connectors". From there, click "Set up" or go to detail page and click "Change SMS connector".
In the openning modal, select "Twilio" and click "Next".
On the next page, you will see a two-column layout with the README content on the left and configuration on the right.
Feel free to follow the README file in place or read the following section to complete the configuration process. If you follow the in-place guide, you can skip the next section.
Set up Twilio SMS connector
Register Twilio account
Create a new account on Twilio. (Jump to the next step if you already have one.)
Set up senders' phone numbers
Go to the Twilio console page and sign in with your Twilio account.
Purchase a phone number under "Phone Numbers" -> "Manage" -> "Buy a number".
ℹ️ Tip
Sometimes you may encounter the situation that SMS service is not supported in specific countries or areas. Pick a number from other regions to bypass.
Once we have a valid number claimed, navigate to the "Messaging" -> "Services". Create a new Message Service by clicking on the button.
Give a friendly service name and choose Notify my users as our service purpose.
Following the next step, choose Phone Number
as Sender Type, and add the phone number we just claimed to this service as a sender.
ℹ️ Note
Each phone number can only be linked with one messaging service.
Get account credentials
We will need the API credentials to make the connector work. Let's begin with the Twilio console page.
Click on the "Account" menu in the top-right corner, then go to the "API keys & tokens" page to get your Account SID
and Auth token
.
Back to "Messaging" -> "Services" settings page starting from the sidebar, and find the Sid
of your service.
Compose the connector JSON
Fill out the accountSID, authToken and fromMessagingServiceSID fields with Account SID
, Auth token
and Sid
of the corresponding messaging service.
You can add multiple SMS connector templates for different cases. Here is an example of adding a single template:
- Fill out the
content
field with arbitrary string-typed contents. Do not forget to leave{{code}}
placeholder for random verification code. - Fill out the
usageType
field with eitherRegister
,SignIn
,ForgotPassword
,Generic
for different use cases. In order to enable full user flows, templates with usageTypeRegister
,SignIn
,ForgotPassword
andGeneric
are required.
Test Twilio SMS connector
You can enter a phone number and click on "Send" to see whether the settings can work before "Save and Done".
That's it. Don't forget to enable connector in sign-in experience.
Config types
Name | Type |
---|---|
accountSID | string |
authToken | string |
fromMessagingServiceSID | string |
templates | Templates[] |
Template Properties | Type | Enum values |
---|---|---|
content | string | N/A |
usageType | enum string | 'Register' | 'SignIn' | 'ForgotPassword' | 'Generic' |
Reference
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 Twilio connector should be available now.
Enable Twilio connector in Sign-in Experience
Switch to the "Sign-in experience" tab, then click the "Sign-up and sign-in" tab.
If it's the first time you enter the tab, you will see a quick introduction about Sign-in Experience and its basic configuration.
Select "Phone number" or "Email address or phone number" for the "Sign-up identifier" to provide sign-up for SMS passwordless sign-in, which may increase your conversion rate.
Finally, click "Save changes" on the bottom right corner.
Testing and Validation
Return to your iOS Swift app. You should now be able to sign in with Twilio. Enjoy!
Further readings
Protect your API For native and single page apps, you'll need to call one or more API endpoints to retrieve and update data.
Learn more about identifying who's who and keeping your API secure.
User management We know you care about user management and activities, as we also do.
Learn more about how to know your users and see the figures like DAU and MAU graphically.
Localization From one regional business to a global corporate, the willingness to offer the best user experience won't change.
You can change current language phrases or add a new language without friction.
Customer IAM series Our serial blog posts about Customer (or Consumer) Identity and Access Management, from 101 to advanced topics and beyond.