How modern browsers work
September 23, 2025
This article dives into how modern browsers work – focusing on Chromium’s architecture and internals, while noting where other engines differ. We’ll explore everything from the networking stack and parsing pipeline to the rendering process via Blink, JavaScript engine via V8, module loading, multi-process architecture, security sandboxing, and developer tooling. The goal is a developer-friendly explanation that demystifies what happens behind the scenes.
Knowing how a modern browser works:
- How it downloads resources
How it parses HTML, JavaScript, and CSS
How it renders the DOM and then paints to the screen
All of these things have a significant impact on the performance of our site.
Having an understanding of how modern browsers work can really help us improve the quality of what we build.
