Implementing REST API CRUD operations

Basically you should follow these principles:

Use the correct HTTP method

Use the correct HTTP status code

HTTP method

HTTP methodOperation
POSTCreate (or all NOT idempotent operations)
GETRead or Retrieve
PUTUpdate all fields of a resource (basically replace it)
PATCHUpdate only part of a resource

HTTP response status

HTTP status codeDescriptionExample
1xxInformational100 Continue
2xxSuccess200 OK
3xxRedirection307 Temporary Redirect
4xxClient Error404 Not Found
5xxServer Error500 Internal Server Error