What Happens When You Type a URL and Press Enter

The short answer: six stages in a fraction of a second

After you press Enter, the browser goes through a chain of steps:

1. Parses the address and checks the cache.
2. DNS — finds the server's IP address from the domain name.
3. TCP — opens a connection to the server.
4. TLS — agrees on encryption (for HTTPS).
5. HTTP — sends a request and receives a response.
6. Rendering — turns HTML, CSS and JavaScript into pixels on the screen.

Each stage takes time, and knowing the chain helps you find out why a site is slow.

Step 1. Parsing the address and the cache

The browser decides what you typed: an address or a search query. If it is an address, it checks the cache for a saved page, files or an already known IP. If they are there and still fresh, some of the next steps are skipped.

Step 2. DNS: finding the IP address

Computers talk using IP addresses, not names. The browser asks a DNS resolver (usually your ISP's or a public one) for the domain's IP. If the resolver does not know, it asks the root servers, then the servers of the domain zone (such as .uz or .com), and finally the authoritative server for your domain.

The answer is cached for the time set in the record (TTL), so repeat visits are faster.

Steps 3–4. TCP and TLS: connection and encryption

• TCP handshake — the client and server exchange service packets and confirm they are ready to send data.
• TLS handshake — the server presents a certificate, and the browser checks that it was issued by a trusted authority and matches the domain. Then both sides agree on encryption keys.

If the certificate has expired or does not match the domain, the browser shows a warning and will not open the page without your consent. Newer protocol versions (HTTP/2, HTTP/3) reduce the number of round trips and let many files travel over a single connection.

Step 5. The HTTP request and the server response

The browser sends a request like this:

GET / HTTP/1.1
Host: example.com
Accept: text/html

The server (often behind a CDN and a reverse proxy such as nginx) passes the request to the application. The application may query the database, build the page and return a response with a status code (200, 301, 404, 500) and HTML in the body.

What matters here is how fast the server responds — TTFB (time to first byte). Slow database queries or no server-side caching show up at this stage.

Step 6. Parsing and rendering the page

Once it has the HTML, the browser:

1. Builds the DOM — the tree of page elements.
2. Discovers resources — CSS, JavaScript, fonts, images — and requests them.
3. Builds the CSSOM — the style model. Until CSS arrives, the browser usually holds off painting content to avoid showing an unstyled page.
4. Runs JavaScript. A plain <script> pauses HTML parsing, which is why scripts are loaded with defer or async.
5. Layout — calculates sizes and positions of elements.
6. Paint and composite — draws pixels and assembles layers on the screen.

At this point the page is visible, but JavaScript may keep loading data and making it interactive.

Where speed is usually lost