When your browser sends a request to a web server, the server answers with an HTTP response. This response is like a digital envelope containing several important parts. First, there is a status code—a short number that tells your browser whether the request was successful, failed, or needs special handling. Next, the response includes headers, which are lines of information about the data being sent, such as its type or how long it should be stored. Finally, there is the body—the main content of the response, often an HTML document that your browser displays as a web page.

Some status codes appear frequently in HTTP responses. A 200 status code means "OK"—your request worked and the server is sending the page you wanted. A 404 status code means "Not Found"—the server could not find the page you asked for. A 500 status code means "Internal Server Error"—something went wrong on the server itself. These codes help browsers and users understand what happened to their request.

When your browser receives a response like the one above, it looks at the status code to decide what to do next. If the code is 200, the browser reads the headers to learn about the data, then processes the HTML body and displays the web page. If the code is 404 or 500, the browser might show an error message instead of the page content. The headers guide the browser on how to handle the data, such as how to display it or whether to store it temporarily.

You can think of an HTTP response like receiving a package in the mail. The status code and headers are like the receipt attached to the outside—they tell you if the delivery was successful and provide details about the package. The body is the content inside the box—the actual item you ordered. Just as you check the receipt and then open the box to see what's inside, your browser checks the status and headers before displaying the web page.