Steps to set up in Google.

1. Sign in with your Google Account. To generate Google Contact API credentials, go to Google API Platform.
    (https://console.cloud.google.com/apis/dashboard)
    Click Enable APIs and Services.

2. In the search bar, look for Google People API.

3. Select the Google People API and enable it.

4. Click Create Credentials.

5. Choose Google People API and the User Data. Then, click Next.

6. Enter the app name and email address. Then, click Save and Continue.

7. Skipped the Third Scope. Save and Continue.

8. Choose Website application and then type the name of the app.

9. In the Authorized JavaScript Origins section, add your company's URL. And in the Authorized redirect URIs section, add your companys URL followed by /google_contact_authentication.

10. After successfully generating Google People API credentials, you will receive a Client ID and Client Secret.

11. Here we can see the Client ID and Secret Key.

12. Also provide users to access the app.

Go to Settings-> Companies Then click on the company name and select the Google Contact tab. Enter the Client id, Client secret and Redirect Url in Credentials.
After entering all the details click on Authenticate.

After successful authentication, now you can sync Google Contacts with Odoo.

In Google, Contacts.

Go to Settings -> Companies -> Select the 'Google Contact' tab -> Then, click the 'Import Contacts' button to import Google contacts into Odoo.

Contacts imported into Odoo.

Export Contact

Select the contacts that need to be exported from Odoo to Google. Then, click on the 'Export to Google' button.

Exported contacts from Odoo to Google.

Delete Contact

Select the contacts that need to be deleted from both Google and Odoo. Then, click on the 'Delete G-Contact' button. If that contact is associated with another model, it will only be deleted from Google.

From Google, the contact has been removed.

Filter Contact

Click the Filter by 'G-contacts' option to filter the synchronized contacts.

Contacts that synced with Google.