When you need to integrate two servers with authentication, you can use Client Credentials Flow in Okta along with Spring Boot and OAuth 2.0. This Client Credential Flow has been recommended for machine to machine authentication. The application that being build is need to securely store its ClientID and Secret with Okta pass in exhange for an access token. Actually, the authentication flow has only two steps, the application needs to pass client credentials to the Okta Authorization server and then if the credentials are true, Okta will responds with an access token.
