Common HTTP Status Codes and When to Implement Them in API or HTTP Response

Status Code	Meaning	When to Implement
200 OK	The request has succeeded	Implement when the request was successful
201 Created	The request has been fulfilled and a new resource has been created	Implement when a new resource has been successfully created
204 No Content	The server has successfully fulfilled the request, but there is no additional content to send in the response	Implement when the request was successful, but there is no content to return
400 Bad Request	The server cannot or will not process the request due to a client error	Implement when there is a problem with the request data, such as missing or invalid parameters
401 Unauthorized	The client must authenticate itself to get the requested response	Implement when the user is not authenticated or the authentication token is invalid
403 Forbidden	The client does not have access rights to the content, so the server is refusing to give the requested response	Implement when the user is authenticated, but does not have permission to access the requested resource
404 Not Found	The server cannot find the requested resource	Implement when the requested resource does not exist
500 Internal Server Error	A generic error message, given when an unexpected condition was encountered and no more specific message is suitable	Implement when there is an unexpected error on the server