Best Frontend Build Tools & CSS for WordPress in 2026

Modular JavaScript polyfill library for ECMAScript features and proposals, whose maintainer said in 2023 he worked alone.

Open source CSS framework that calls itself a design system for everyone, with code under MIT and docs under CC BY 3.0.

Utility-first CSS framework: a page is styled with classes composed directly in its markup.

Cross-browser CSS animation library that its homepage sells as just-add-water.

Variant-focused CSS-in-JS library that has gone unmaintained since 2023.

Incremental Rust bundler built into Next.js, where it is the default.

MIT-licensed static module bundler for modern JavaScript applications.

CSS file convention that scopes class names locally by default, to avoid clashes between components' styles.

Scroll animation library driven by data-aos attributes in the HTML.

Accessible, unstyled React UI component library from WorkOS, with a styled companion called Radix Themes.

Copy-and-own React component collection: the source lands in your project, not in a dependency.

Browser feature-detection library for serving newer features only to browsers that support them.

Template-literal CSS-in-JS library for React, in maintenance mode since 2025 but still shipping releases.

CSS-in-JS library with a framework-agnostic package and a React one that renders on the server without setup.

Alternative to a CSS reset that aims to make browsers render elements more consistently.

JavaScript module bundler built on standard ES modules, for libraries and apps.

Frontend build tool made by Vue.js creator Evan You, with production builds that run on the Rust-based Rolldown.

Family of responsive front-end frameworks for sites and apps, with a separate one for HTML email.

Zero-runtime CSS-in-TypeScript library with official integrations for webpack, esbuild, Vite and Next.js.

Hookable, standards-based JavaScript module loader that keeps working in older browsers back to IE11.

Lightweight, modular front-end framework from YOOtheme for building web interfaces.

Free, open source CSS framework of ready-to-use components, credited to Jeremy Thomas and written in Sass.

Unstyled UI component library from Tailwind Labs, published as React and Vue packages.

Bare responsive CSS boilerplate designed as a starting point rather than a UI framework.

Scoped CSS-in-JS library for JSX that Next.js configures automatically.

React component library of accessible parts for web apps and design systems, from Chakra Systems.

Vue 3 UI component library, production-ready since February 2022, that its site addresses to designers as well as developers.

Microsoft's design system and UI component library, in React and Web Components.

Google's Material Design implemented as a React component library, from the company Material UI SAS.

AMD module loader for JavaScript in the browser, under BSD or MIT terms.

Design system that Ant Group bills as enterprise-class, with antd as its React UI component library.

Cloudflare-hosted polyfill service on cdnjs that serves the polyfills each visitor's browser requires.

Unmaintained CSS-in-JS authoring tool that uses JavaScript as the host language for styles.

Preprocessor language that extends CSS without breaking backwards compatibility, licensed under Apache-2.0.

Component library for React with its own hooks, styled with CSS Modules by default.

Compiled CSS-in-JS styling system from Meta that turns styles into atomic class names.

Tailwind CSS component plugin, free and open-source and built by its community.

Palantir's open-source React toolkit for complex, data-dense desktop web interfaces.

Hosted polyfill service whose domain changed hands in 2024 and then served malware.

GitHub's own design system and component library, including the Octicons SVG icon set.

Responsive CSS and UI component framework for human-friendly HTML, counted with its official community fork.

On-demand atomic CSS engine whose utilities all come from presets rather than a built-in core.