Learn Grid Lanes to create masonry layouts in pure CSS. Absorb the possibilities with the Field Guide’s interactive playground. Return to the cheat sheet. Get inspired by six real examples with dozens...

A from-the-ground-up walkthrough of how modern LLMs work, from tokens to transformer blocks to the next-token loop

You’ve almost certainly encountered Conventional Commits before. It may have reared its ugly head in the changelog of an open source project you’ve used. It may have been the enforced commit format fo...

My own personal thoughts and opinions on AI effects and usage, and how those have evolved over time

The CodePen Compiler powers 2.0 editor: process and build your code with configurable blocks.

Today we're releasing the alpha of npmx.dev – a fast, modern browser for the npm registry, built in the open by a growing community.

The Web streams API has become ubiquitous in JavaScript runtimes but was designed for a different era. Here's what a modern streaming API could (should?) look like.

I'm scared, I'm excited, and I'm exhausted by the pace of change. All of those things can be true at the same time. This blog post is a grounded take on living through AI's inflection point, why the b...

AI can serve us as a force multiplier, augmenting our own agency and making the most of our own effort, hard work and value. Not by replacing it.

This is a step-by-step guide on how I use Chrome DevTools (DevTools from now on) to detect Web Performance issues on a website, as well as validate hypotheses to fix some of the problems found. Discl...

Three decades of making things on the internet

Subgrid allows us to extend a grid template down through the DOM tree, so that deeply-nested elements can participate in the same grid layout. At first glance, I thought this would be a helpful conven...

A response to ‘But ChatGPT said…’

The protocol is the API.

If you thought 2024 was packed with amazing new CSS, well, you're right. But so is 2025 and it keeps looking bright. Check out our list of the best stuff with easy-to-reference examples.

A web developers guide to browser internals

The personal blog of Thomas Steiner

Walkthrough of the various parts and concepts in Bluesky's AT Protocol (ATProto), the types of servers involved and how it all fits together

Parcel v2.14.0 added support for React Server Components. This post is a deep dive into the internals: how RSCs integrate with a bundler, what directives like "use client" actually do, how code splitt...

How well do you know JavaScript's Date class?

Background If you’re new to scroll-driven animations, welcome!

We’re taught to eliminate duplication at all costs. But the wrong abstraction is far more expensive than a little copy-paste. Here’s why.

Slides and video for my talk on how React has been developed and current concerns in the community