RPC (Remote Procedure Call) APIs and REST (Representational State Transfer) APIs have different approaches to communication and authentication. RPC APIs: Authentication can be more complex and is often embedded within the service calls themselves, sometimes requiring specific provisions for the caller and the service. REST APIs: Authentication typically relies on standardized methods such as HTTP headers, including Basic Auth, OAuth tokens, or API keys, making it more straightforward and standardized across different services. Reference: Cisco DevNet Documentation - APIs Cisco DevNet Associate Certification Guide