These are the standard codes that refer to the predefined status of the task at the server. Following are the status codes formats available:

• 1xx - represents informational responses
• 2xx - represents successful responses
• 3xx - represents redirects
• 4xx - represents client errors
• 5xx - represents server errors

Most commonly used status codes are:

• 200 - success/OK
• 201 - CREATED - used in POST or PUT methods.
• 304 - NOT MODIFIED - used in conditional GET requests to reduce the bandwidth use of the network. Here, the body of the response sent should be empty.
• 400 - BAD REQUEST - This can be due to validation errors or MISSING input data.
• 401- UNAUTHORIZED - This is returned when there is no valid AUTHENTICATION credentials sent along with the request.
• 403 - FORBIDDEN - sent when the user does not have access (or is forbidden) to the resource.
• 404 - NOT FOUND - Resource method is not available.
• 500 - INTERNAL SERVER ERROR - server threw some exceptions while running the method.
• 502 - BAD GATEWAY - Server was not able to get the response from another upstream server.