What Happens When You Type a URL in the Browser?

Typing a URL triggers a fascinating 10-step journey before pixels appear on screen. It starts with DNS resolution — the browser checks its cache, then queries recursive resolvers to translate the domain into an IP address. Next comes the TCP three-way handshake establishing a reliable connection, followed by TLS negotiation for HTTPS (certificate verification, key exchange).

The browser sends an HTTP request, the server processes it and returns a response. Then the real rendering begins: the browser parses HTML into a DOM tree, CSS into a CSSOM, merges them into a render tree, calculates layout (reflow), and finally paints pixels to the screen. JavaScript execution can block parsing unless deferred.

Understanding this pipeline helps developers optimize load times — from DNS prefetching to critical CSS inlining to resource prioritization.