Authentication and Authorization for RESTful APIs: Steps to Getting Started
Why do APIs require authentication in the first place? Users don't always need keys for read-only APIs. However, most commercial APIs require permission via API keys or other ways. Users might make an unlimited number of API calls without needing to register if your API had no security. Allowing limitless requests would make it impossible to develop a business structure for your API. Furthermore, without authentication, it would be difficult to link requests to individual user data.