Login with Google

For web applications, you can set up your signin button two different ways:

• Use your own application code for the button.
• Use Google's pre-built sign-in or OneTap flows.

Application code configuration#

To use your own application code:

1. In the Google Cloud console, go to the Consent Screen configuration page. The consent screen is the view shown to your users when they consent to signing in to your app.

2. Under Authorized domains, add your Supabase project's domain, which has the form <PROJECT_ID>.supabase.co.

3. Configure the following non-sensitive scopes:

   • .../auth/userinfo.email
   • ...auth/userinfo.profile
   • openid

4. Go to the API Credentials page.

5. Click Create credentials and choose OAuth Client ID.

6. For application type, choose Web application.

7. Under Authorized JavaScript origins, add your site URL.

8. Under Authorized redirect URLs, enter the callback URL from the Supabase dashboard. Expand the Google Auth Provider section to display it.

   The redirect URL is visible to your users. You can customize it by configuring custom domains.

9. When you finish configuring your credentials, you will be shown your client ID and secret. Add these to the Google Auth Provider section of the Supabase Dashboard.

   In local development, you can add the client ID and secret to your config.toml file.

Google pre-built configuration#

To use Google's pre-built signin buttons:

1. In the Google Cloud console, go to the Consent Screen configuration page. The consent screen is the view shown to your users when they consent to signing in to your app.
2. Configure the screen to your liking, making sure you add links to your app's privacy policy and terms of service.
3. Go to the API Credentials page.
4. Click Create credentials and choose OAuth Client ID.
5. For application type, choose Web application.
6. Under Authorized JavaScript origins and Authorized redirect URLs, add your site URL. This is the URL of the website where the signin button will appear, not your Supabase project domain.
7. When you finish configuring your credentials, you will be shown your client ID. Add this to the Authorized Client IDs field in the Google Auth Provider section of the Supabase Dashboard. Leave the OAuth client ID and secret blank. You don't need them when using Google's pre-built approach.

Application code#

To use your own application code for the signin button, call the signInWithOAuth method (or the equivalent for your language).

For an implicit flow, that's all you need to do. The user will be taken to Google's consent screen, and finally redirected to your app with an access and refresh token pair representing their session.

For a PKCE flow, for example in Server-Side Auth, you need an extra step to handle the code exchange. When calling signInWithOAuth, provide a redirectTo URL which points to a callback route. This redirect URL should be added to your redirect allow list.

At the callback endpoint, handle the code exchange to save the user session.

After a successful code exchange, the user's session will be saved to cookies.

Saving Google tokens#

The tokens saved by your application are the Supabase Auth tokens. Your app might additionally need the Google OAuth 2.0 tokens to access Google services on the user's behalf.

On initial login, you can extract the provider_token from the session and store it in a secure storage medium. The session is available in the returned data from signInWithOAuth (implicit flow) and exchangeCodeForSession (PKCE flow).

Google does not send out a refresh token by default, so you will need to pass parameters like these to signInWithOAuth() in order to extract the provider_refresh_token:

Google pre-built#

Most web apps and websites can utilize Google's personalized sign-in buttons, One Tap or automatic sign-in for the best user experience.

1. Load the Google client library in your app by including the third-party script:

   
   

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   <script src="https://accounts.google.com/gsi/client" async></script>

   
   

2. Use the HTML Code Generator to customize the look, feel, features and behavior of the Sign in with Google button.

3. Pick the Swap to JavaScript callback option, and input the name of your callback function. This function will receive a CredentialResponse when sign in completes.

   To make your app compatible with Chome's third-party-cookie phase-out, make sure to set data-use_fedcm_for_prompt to true.

   Your final HTML code might look something like this:

   
   

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   <div

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   id="g_id_onload"

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   data-client_id="<client ID>"

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   data-context="signin"

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   data-ux_mode="popup"

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   data-callback="handleSignInWithGoogle"

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   data-nonce=""

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   data-auto_select="true"

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   data-itp_support="true"

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   data-use_fedcm_for_prompt="true"

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   ></div>

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   <div

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   class="g_id_signin"

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   data-type="standard"

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   data-shape="pill"

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   data-theme="outline"

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   data-text="signin_with"

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   data-size="large"

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   data-logo_alignment="left"

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   ></div>

   
   

4. Create a handleSignInWithGoogle function that takes the CredentialResponse and passes the included token to Supabase. The function needs to be available in the global scope for Google's code to find it.

   
   

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   async function handleSignInWithGoogle(response) {

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   const { data, error } = await supabase.auth.signInWithIdToken({

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   provider: 'google',

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   token: response.credential,

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   })

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   }

   
   

5. (Optional) Configure a nonce. The use of a nonce is recommended for extra security, but optional. The nonce should be generated randomly each time, and it must be provided in both the data-nonce attribute of the HTML code and the options of the callback function.

   
   

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   async function handleSignInWithGoogle(response) {

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   const { data, error } = await supabase.auth.signInWithIdToken({

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   provider: 'google',

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   token: response.credential,

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   nonce: '<NONCE>',

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   })

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   }

   
   

   Note that the nonce should be the same in both places, but because Supabase Auth expects the provider to hash it (SHA-256, hexadecimal representation), you need to provide a hashed version to Google and a non-hashed version to signInWithIdToken.

   You can get both versions by using the in-built crypto library:

   
   

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   // Adapted from https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/digest#converting_a_digest_to_a_hex_string

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   const nonce = btoa(

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   String.fromCharCode(...crypto.getRandomValues(new Uint8Array(32))),

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   );

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   const encoder = new TextEncoder();

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   const encodedNonce = encoder.encode(nonce);

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   crypto.subtle.digest("SHA-256", encodedNonce).then((hashBuffer) => {

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   const hashArray = Array.from(new Uint8Array(hashBuffer));

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   const hashedNonce = hashArray

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   .map((b) => b.toString(16).padStart(2, "0"))

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   .join("");

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   }

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   // Use 'hashedNonce' when making the authentication request to Google

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   // Use 'nonce' when invoking the supabase.auth.signInWithIdToken() method