Migrating to Tailwind CSS v4: What You Need to Know

Tailwind CSS v4 represents the most significant update to the framework since its inception. With a completely rewritten engine built in Rust and a new CSS-first configuration approach, v4 offers dramatic performance improvements and an even better developer experience.

What's New in v4

CSS-First Configuration

Say goodbye to `tailwind.config.js`. In v4, you define your design tokens directly in CSS using the `@theme` directive:

@theme {
  --color-primary: #10b981;
  --color-secondary: #06b6d4;
  --font-sans: 'Inter', system-ui;
}

Lightning-Fast Build Times

The new Oxide engine, written in Rust, delivers build times that are up to 10x faster than v3. This is especially noticeable in large projects with thousands of utilities.

Native CSS Features

V4 embraces modern CSS features like cascade layers, container queries, and the `:has()` selector, reducing the need for JavaScript-based solutions.

Migration Tips

**Start Fresh** - Consider starting with a new configuration rather than migrating existing configs
**Test Thoroughly** - Some utility classes may have subtle differences
**Use the Upgrade Guide** - The official migration guide covers edge cases

Tailwind v4 is a massive leap forward. Start experimenting today!