HTTP & HTTPS

What is HTTP?

HTTP (HyperText Transfer Protocol) is the foundation of data communication on the World Wide Web. It defines how messages are formatted and transmitted between web browsers (clients) and web servers.

How HTTP Works

1. You type a URL in your browser (e.g., http://example.com).
2. The browser sends an HTTP Request to the server.
3. The server processes the request and sends back an HTTP Response (HTML, CSS, images, etc.).
4. The browser renders the content on screen.

HTTP Methods

• GET — Retrieve data from the server. (Loading a webpage)
• POST — Send data to the server. (Submitting a form)
• PUT — Update an existing resource.
• DELETE — Remove a resource.
• PATCH — Partially update a resource.

HTTP Status Codes

• 200 OK — Success! Request completed normally.
• 301 Moved Permanently — The resource has a new URL.
• 400 Bad Request — The client sent an invalid request.
• 401 Unauthorized — Authentication required.
• 403 Forbidden — Server refuses to fulfil the request.
• 404 Not Found — The requested resource doesn't exist.
• 500 Internal Server Error — Something went wrong on the server.

HTTPS — Secure HTTP

HTTPS is HTTP with TLS/SSL encryption. It provides three critical protections:

• Encryption — Data is scrambled so only the intended recipient can read it.
• Authentication — Verifies you're talking to the real server (via certificates).
• Integrity — Ensures data hasn't been tampered with in transit.

Always look for the 🔒 padlock icon in your browser's address bar — it confirms HTTPS is active.

HTTP/1.1 vs HTTP/2 vs HTTP/3

• HTTP/1.1 — One request at a time per connection. Still widely used.
• HTTP/2 — Multiple requests simultaneously over one connection (multiplexing). Much faster.
• HTTP/3 — Built on QUIC (UDP-based). Even lower latency. The future of the web.

What's Next?

Learn how domain names become IP addresses with DNS Explained, or explore Cyber Security to understand how attackers exploit HTTP vulnerabilities.