RESTful web services return HTTP status codes with the response; what is the role of status codes?

• A. Provide feedback for the outcome
• B. Define resource structure
• C. Manage authentication tokens
• D. Encrypt the response

Answer: (A)

HTTP status codes provide feedback on the outcome of a client's request. They tell the client what happened: a successful operation is indicated by 2xx codes, something was wrong with the request is shown by 4xx codes, and server-side problems are indicated by 5xx codes, with 3xx codes signaling that the client should take a different action (like following a redirect). This feedback guides the next steps the client should take—whether to display a message, retry, prompt for authentication, or use information in headers (for example, a Location header when a new resource is created). They aren’t used to define the resource’s structure (that’s in the response body), nor to manage authentication tokens or encryption. For instance, 201 Created often accompanies the URL of the new resource, 400 means bad input, 401 requires authentication, and 204 means the request succeeded but there’s no content to return.