what is core API code example

Example: core components of api

1-An action showing HTTP methods like
GET, PUT, POST, DELETE.
2-Uniform Resource Identifier (URI),
 which is the identifier for the resource on the server.
3-HTTP Version, which indicates HTTP
version, for example-HTTP v1.1.
4-Request Header, which carries metadata
(as key-value pairs) for the HTTP Request message.
Metadata could be a client (or browser) type,
  format supported by the client, format 
of a message body format,
  cache settings, and so on.
5-Request Body, which indicates the
message content or resource representation.