Glossary · Internet & Web

HTTP (HyperText Transfer Protocol)

HTTP is the request-and-response protocol browsers and servers use to exchange web pages, files and API data, with methods, headers and status codes.

Updated October 6, 2026

HTTP (HyperText Transfer Protocol) is the application protocol of the web. A client sends a request containing a method, path and headers, and the server replies with a status code, headers and usually a body.

Why it matters

Almost everything online uses HTTP: pages, images, APIs, webhooks and health checks. Understanding its methods and status codes helps you diagnose problems. Plain HTTP is unencrypted, so modern sites use HTTPS, which is HTTP carried inside TLS.

Newer versions such as HTTP/2 and HTTP/3 change how data is carried but keep the same request and response ideas, so skills transfer directly.

Example

GET /index.html HTTP/1.1
Host: example.com

HTTP/1.1 200 OK
Content-Type: text/html

Common methods are GET (read), POST (create), PUT or PATCH (update) and DELETE.

Common mistakes

  • Treating HTTP as stateful; every request is independent unless cookies or tokens link them.
  • Serving a site over plain HTTP, exposing logins and content to interception.
  • Confusing HTTP with HTML, or with the whole internet.

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