An HTTP response is the message a server sends back to a client after processing an HTTP request. It contains a status code, headers, and an optional body with data. Responses can include HTML, JSON, files, or error messages. The status code communicates the result—such as 200 (OK), 404 (Not Found), or 500 (Server Error). Responses are the backbone of all interactions on the web.
Why it matters
Understanding responses helps developers diagnose API issues, interpret error messages, and optimize frontend–backend data exchange. Clear, predictable responses improve reliability and user experience.
Examples
Returning a JSON object from a REST API or serving an HTML page via a GET request. Lessons like How Servers Send Responses explore response behavior.