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Build a custom flow for authenticating with OAuth connections

Warning

This guide is for users who want to build a custom user interface using the Clerk API. To use a prebuilt UI, use the Account Portal pages or prebuilt components.

Before you start

You must configure your application instance through the Clerk Dashboard for the social connection(s) that you want to use. Visit the appropriate guide for your platform to learn how to configure your instance.

Create the sign-up and sign-in flow

The following example will both sign up and sign in users, eliminating the need for a separate sign-up page. However, if you want to have separate sign-up and sign-in pages, the sign-up and sign-in flows are equivalent, meaning that all you have to do is swap out the SignIn object for the SignUp object using the useSignUp() hook.

The following example:

  1. Accesses the object using the useSignIn() hook.
  2. Starts the authentication process by calling . This method requires a redirectUrl param, which is the URL that the browser will be redirected to once the user authenticates with the identity provider.
  3. Creates a route at the URL that the redirectUrl param points to. The following example names this route /sso-callback. This route should either render the prebuilt <AuthenticateWithRedirectCallback/> component or call the method if you're not using the prebuilt component.

The following example shows two files:

  1. The sign-in page where the user can start the authentication flow.
  2. The SSO callback page where the flow is completed.
app/sign-in/page.tsx
'use client'

import * as React from 'react'
import { OAuthStrategy } from '@clerk/types'
import { useSignIn } from '@clerk/nextjs'

export default function OauthSignIn() {
  const { signIn } = useSignIn()

  if (!signIn) return null

  const signInWith = (strategy: OAuthStrategy) => {
    return signIn
      .authenticateWithRedirect({
        strategy,
        redirectUrl: '/sign-in/sso-callback',
        redirectUrlComplete: '/',
      })
      .then((res) => {
        console.log(res)
      })
      .catch((err: any) => {
        // See https://clerk.com/docs/custom-flows/error-handling
        // for more info on error handling
        console.log(err.errors)
        console.error(err, null, 2)
      })
  }

  // Render a button for each supported OAuth provider
  // you want to add to your app. This example uses only Google.
  return (
    <div>
      <button onClick={() => signInWith('oauth_google')}>Sign in with Google</button>
    </div>
  )
}
app/sign-in/sso-callback/page.tsx
import { AuthenticateWithRedirectCallback } from '@clerk/nextjs'

export default function Page() {
  // Handle the redirect flow by calling the Clerk.handleRedirectCallback() method
  // or rendering the prebuilt <AuthenticateWithRedirectCallback/> component.
  // This is the final step in the custom OAuth flow.
  return <AuthenticateWithRedirectCallback />
}

The following example will both sign up and sign in users, eliminating the need for a separate sign-up page.

The following example:

  1. Uses the hook to access the startSSOFlow() method.
  2. Calls the startSSOFlow() method with the strategy param set to oauth_google, but you can use any of the . The optional redirect_url param is also set in order to redirect the user once they finish the authentication flow.
    • If authentication is successful, the setActive() method is called to set the active session with the new createdSessionId.
    • If authentication is not successful, you can handle the missing requirements, such as MFA, using the or object returned from startSSOFlow(), depending on if the user is signing in or signing up. These objects include properties, like status, that can be used to determine the next steps. See the respective linked references for more information.
app/(auth)/sign-in.tsx
import React, { useCallback, useEffect } from 'react'
import * as WebBrowser from 'expo-web-browser'
import * as AuthSession from 'expo-auth-session'
import { useSSO } from '@clerk/clerk-expo'
import { View, Button } from 'react-native'

export const useWarmUpBrowser = () => {
  useEffect(() => {
    // Preloads the browser for Android devices to reduce authentication load time
    // See: https://docs.expo.dev/guides/authentication/#improving-user-experience
    void WebBrowser.warmUpAsync()
    return () => {
      // Cleanup: closes browser when component unmounts
      void WebBrowser.coolDownAsync()
    }
  }, [])
}

// Handle any pending authentication sessions
WebBrowser.maybeCompleteAuthSession()

export default function Page() {
  useWarmUpBrowser()

  // Use the `useSSO()` hook to access the `startSSOFlow()` method
  const { startSSOFlow } = useSSO()

  const onPress = useCallback(async () => {
    try {
      // Start the authentication process by calling `startSSOFlow()`
      const { createdSessionId, setActive, signIn, signUp } = await startSSOFlow({
        strategy: 'oauth_google',
        // For web, defaults to current path
        // For native, you must pass a scheme, like AuthSession.makeRedirectUri({ scheme, path })
        // For more info, see https://docs.expo.dev/versions/latest/sdk/auth-session/#authsessionmakeredirecturioptions
        redirectUrl: AuthSession.makeRedirectUri(),
      })

      // If sign in was successful, set the active session
      if (createdSessionId) {
        setActive!({ session: createdSessionId })
      } else {
        // If there is no `createdSessionId`,
        // there are missing requirements, such as MFA
        // Use the `signIn` or `signUp` returned from `startSSOFlow`
        // to handle next steps
      }
    } catch (err) {
      // See https://clerk.com/docs/custom-flows/error-handling
      // for more info on error handling
      console.error(JSON.stringify(err, null, 2))
    }
  }, [])

  return (
    <View>
      <Button title="Sign in with Google" onPress={onPress} />
    </View>
  )
}
OAuthView.swift
import SwiftUI
import Clerk

struct OAuthView: View {
  var body: some View {
    // Render a button for each supported OAuth provider
    // you want to add to your app. This example uses only Google.
    Button("Sign In with Google") {
      Task { await signInWithOAuth(provider: .google) }
    }
  }
}

extension OAuthView {

  func signInWithOAuth(provider: OAuthProvider) async {
    do {
      // Start the sign-in process using the selected OAuth provider.
      let result = try await SignIn.authenticateWithRedirect(strategy: .oauth(provider: provider))

      // It is common for users who are authenticating with OAuth to use
      // a sign-in button when they mean to sign-up, and vice versa.
      // Clerk will handle this transfer for you if possible.
      // Therefore, a TransferFlowResult can be either a SignIn or SignUp.

      switch result {
      case .signIn(let signIn):
        switch signIn.status {
        case .complete:
          // If sign-in process is complete, navigate the user as needed.
          dump(Clerk.shared.session)
        default:
          // If the status is not complete, check why. User may need to
          // complete further steps.
          dump(signIn.status)
        }
      case .signUp(let signUp):
        switch signUp.status {
        case .complete:
          // If sign-up process is complete, navigate the user as needed.
          dump(Clerk.shared.session)
        default:
          // If the status is not complete, check why. User may need to
          // complete further steps.
          dump(signUp.status)
        }
      }

    } catch {
      // See https://clerk.com/docs/custom-flows/error-handling
      // for more info on error handling.
      dump(error)
    }
  }
}

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