HTTP Request Lifecycle

When you type a URL and press Enter, a chain of events fires off before you see anything on screen. Here is the full lifecycle:

1. DNS Lookup — the browser resolves the domain name to an IP address
2. TCP Connection — a three-way handshake establishes a reliable connection
3. HTTP Request — the browser sends the request (method, path, headers)
4. HTTP Response — the server sends back a status code, headers, and body
5. Render — the browser parses HTML/CSS/JS and paints the page

Click the button below to watch each phase animate in sequence.

Every HTTP request uses a method that tells the server what action to perform:

• GET — retrieve data (e.g. loading a page)
• POST — submit data (e.g. submitting a form)
• PUT — replace a resource entirely
• DELETE — remove a resource

Build a request below to see the raw HTTP format:

Tip: Headers provide metadata about the request. Content-Type tells the server the format of the body. Authorization carries credentials for protected resources.

The server responds with a status code that indicates the result. They are grouped by category:

1. What is the first thing a browser does when you enter a URL?

2. Which HTTP method is used to submit data to a server?

3. What does a 404 status code mean?