An <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Messages">HTTP (Hypertext Transfer Protocol)</a> message is a structured format used for communication between a client (typically a web browser or application) and a server.
<h2>HTTP Request Message Structure:</h2>
An HTTP request message is sent by a client to request a resource from a server.
<ul>
<li>
Request Line:
<ul>
<li><code>Method</code>: The HTTP method or verb indicating the action to be performed (e.g., GET, POST, PUT, DELETE).</li>
<li><code>Request Target</code>: The URL or path to the requested resource on the server.</li>
<li><code>HTTP Version</code>: The version of the HTTP protocol being used (e.g., HTTP/1.1).</li>
</ul>
</li>
<li>
Headers: Key-value pairs that provide additional information about the request, such as the <code>User-Agent</code>, <code>Accept-Encoding</code>, and <code>Host</code>.
</li>
<li>
Optional Body: Some HTTP requests, like <code>POST</code> or <code>PUT</code>, may include a request body containing data to be sent to the server.
</li>
</ul>
<pre class="shiki github-dark shaku"><code>GET /example.html HTTP/1.1Host: www.example.comUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.82 Safari/537.36Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8</code></pre>
<h2>HTTP Response Message Structure:</h2>
An HTTP response message is sent by a server in response to an HTTP request.
<ul>
<li>
Status Line:
<ul>
<li><code>HTTP Version</code>: The version of the HTTP protocol being used.</li>
<li><code>Status Code</code>: A three-digit numeric code indicating the result of the request (e.g., 200 for OK, 404 for Not Found, 500 for Internal Server Error).</li>
<li><code>Reason Phrase</code>: A brief textual description of the status code.</li>
</ul>
</li>
<li>
Headers: Key-value pairs providing metadata about the response, such as Content-Type, Content-Length, and Server.
</li>
<li>
Optional Body: The actual content of the requested resource, if applicable. For example, HTML content for a web page or an image file.
</li>
</ul>
<pre class="shiki github-dark shaku"><code>HTTP/1.1 200 OKDate: Sun, 02 Oct 2023 12:00:00 GMTServer: Apache/2.4.41 (Unix)Content-Length: 1234Content-Type: text/html&lt;!DOCTYPE html&gt;&lt;html&gt;&lt;head&gt; &lt;title&gt;Example Page&lt;/title&gt;&lt;/head&gt;&lt;body&gt; &lt;h1&gt;Hello, World!&lt;/h1&gt;&lt;/body&gt;&lt;/html&gt;</code></pre>

HTTP messages explained

This is good-to-known knowledge, MDN doc explains it very well.…