Public APIs
Public APIs are called open APIs. This term refers to APIs that are meant to be available for use by any third party, often without any access limitation. These APIs typically involved no authentication and authorization.
Partner APIs
The APIs That Fall into this category are meant to be available only to specifically selected and authorized partners, such as external developers, system integrator companies, wish listed external protocols Ips.
Internal APIs (Private APIs)
These APIs are meant for internal use only connected different services owned by the same organization, and are often hosted within the same virtual private network, web form, or private cloud.
Composite APIs
These APIs combine multiple APIs to execute a sequence of related or independent operations with single call. In nutshell, they allow developers to access several endpoints at the same times.
References
Building Web APIs with ASP.NET Core O’Reilly ISBN: 9781633439481