You can create Developer Edition Account at https://developer.okta.com/signup/

https://developer.okta.com/code/rest/

• Rest api: https://developer.okta.com/docs/reference/api/users/#create-user-with-password

curl -v -X POST \
-H "Accept: application/json" \
-H "Content-Type: application/json" \
-H "Authorization: SSWS ${api_token}" \
-d '{
  "profile": {
    "firstName": "Isaac",
    "lastName": "Brock",
    "email": "[email protected]",
    "login": "[email protected]",
    "mobilePhone": "555-415-1337"
  },
  "credentials": {
    "password" : { "value": "tlpWENT2m" }
  }
}' "https://${yourOktaDomain}/api/v1/users?activate=true"

https://developer.okta.com/docs/guides/add-an-external-idp/google/before-you-begin/

https://developer.okta.com/docs/guides/add-an-external-idp/google/create-an-app-at-idp/

• Create an App at the Identity Provider

• Access: https://console.developers.google.com/
• Select Credentials => Create Credentials => OAuth client ID => Select the Web application application type => Name your OAuth 2.0 client => Fill Authorized redirect URIs: add the Okta redirect URI. (ex: https://dev-xxxxxxx.okta.com/oauth2/v1/authorize/callback) => click Create => Save the OAuth Client ID and Client Secret values so you can add them to the Okta configuration in the next section.

• Create an Identity Provider in Okta

• Access: https://dev-xxxxxxx-admin.okta.com/dev/console
• Hover over Users and then select Social & Identity Providers
• Add Identity Provider -> Add an Identity Provider -> Add Google
• Fill Client ID and Client Secret from previous step (Google OAuth credentials)

• Register an App in Okta

• In your Okta org, click Applications, and then Add Application
• Select the appropriate platform for your use case, enter a name for your new application, and then click Next.
• In Allowed grant types: Enable Implicit + Check both Allow ID Token with implicit grant type + Allow Access Token with implicit grant type
• Add Custom Login redirect URIs: okta://com.okta.dev-xxxxxxx
• Scroll to the Client Credentials section and copy the client ID that you use to complete the Authorize URL in the next step

• Create the Authorization URL https://${yourOktaDomain}/oauth2/v1/authorize?idp=0oaaq9pjc2ujmFZexample&client_id=GkGw4K49N4UEE1example&response_type=id_token%20token&response_mode=fragment&scope=openid&redirect_uri=${Login redirect URI}&state=any&nonce=any&prompt=login

After successful authentication, the user is redirected to the redirect URI that you specified, along with an #id_token= and &access_token fragment in the URL Get user info from access token:

curl --location --request GET 'https://dev-xxxxxxx.okta.com/oauth2/v1/userinfo' \
--header 'Accept: application/json' \
--header 'Authorization: Bearer access_token'