How Browsers Work

From response bytes to painted pixels.

Web Platform1 minInspired by Browser internals essays

md for AI Agents

The browser resolves DNS, opens transport, streams HTML, and starts parsing before the full response arrives.

Render tree

DOM and CSSOM combine into a render tree for visible elements. Scripts can block parsing unless deferred.

Layout paint composite

Layout computes geometry
Paint fills pixels
Composite merges layers

Performance hint

Prefer transform/opacity animation and profile with real tools instead of guessing.