Tailwind CSS v4: What Changed and How to Migrate
Tailwind CSS v4 introduces a new engine, CSS-first configuration, and faster builds. Here is everything you need to know.
Abdur Razzak
Full-Stack Web Developer
The New Oxide Engine
Tailwind CSS v4 replaces the JavaScript-based engine with Oxide, a high-performance Rust engine. Builds that previously took seconds now finish in milliseconds, even for large projects with thousands of utility classes.
CSS-First Configuration
In v4 you configure Tailwind in your CSS file using @theme instead of a tailwind.config.js file. Custom colors, fonts, and breakpoints are now defined as CSS variables, making it easier to share them across your design system.
Breaking Changes
Several class names were renamed for consistency. The shadow, rounded, and blur scales were updated. The PostCSS plugin setup also changed. Run the official migration guide and use the v4 upgrade tool to automate most changes.
Should You Migrate Now?
If you are starting a new project, absolutely use v4. For existing projects, wait until the plugins and third-party libraries you depend on have released v4-compatible versions.
