HTTP Explained

How Browsers Talk to Servers

Every time you open a web page your browser talks to a web server using a protocol called HTTP. This communication defines how requests are sent and how responses are received. It is the language of the web. Understanding HTTP helps you understand how the internet delivers content, runs applications and loads websites.

What is HTTP

HTTP stands for Hypertext Transfer Protocol. It is a set of rules that browsers and servers follow to communicate. HTTP is:

• Simple

• Text based

• Stateless

Stateless means the server does not remember previous requests unless the application uses cookies or sessions.

How HTTP works step by step

Step 1. You type a URL

Example: https://example.com/products

Step 2. Browser resolves the domain name to an IP address

DNS gives the browser the server’s IP address.

Step 3. Browser connects to the server

This connection may use TCP or QUIC depending on HTTP version.

Step 4. Browser sends an HTTP request

The request includes:

• Method

• Headers

• Path

• Optional body

Step 5. Server processes the request

Server application checks routing, logic and data.

Step 6. Server sends an HTTP response

The response includes:

• Status code

• Headers

• Body (HTML, JSON, images)

Step 7. Browser displays the page

The browser interprets HTML and loads additional resources.

HTTP methods explained

GET

Retrieve a resource. Used for loading pages or fetching data.

POST

Send data to the server. Used in forms and APIs.

PUT

Update an existing resource.

DELETE

Remove a resource.

PATCH

Partially update data.

These methods help create predictable APIs.

HTTP status codes explained

2xx Success

200 OK 201 Created

3xx Redirection

301 Permanent redirect 302 Temporary redirect

4xx Client errors

400 Bad request 404 Not found 429 Too many requests

5xx Server errors

500 Server error 503 Service unavailable

These codes help browsers and developers understand what happened.

HTTP headers explained

Headers carry metadata.

Common request headers:

• User Agent

• Accept

• Authorization

Common response headers:

• Content Type

• Cache Control

• Set Cookie

Headers influence caching, security and behavior.

Why HTTP is important

HTTP powers:

• Websites

• APIs

• Mobile apps

• Browser communication

• Web services

• CDNs

• Cloud applications

Any modern internet application uses HTTP or HTTPS.

Evolution of HTTP

HTTP evolved many times.

HTTP 1.0

• One request per connection.

HTTP 1.1

• Persistent connections and caching.

HTTP 2

• Multiplexing and faster loading.

HTTP 3

• Uses QUIC and UDP for even better performance.

Each upgrade focused on performance and reliability.

Conclusion

HTTP defines how browsers request resources and how servers respond. It is simple yet powerful. It forms the core of modern web communication. A solid understanding of HTTP makes learning HTTPS, TLS, routing and APIs easier.