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What am I reading?

This document provides an overview of Stylable and its features, and serves as a quick guide for getting started. Each chapter focuses on one core feature of Stylable, introducing a problem or need, showing how CSS might address it, and then how Stylable can be used to simplify the solution. This handbook is not a complete reference for Stylable, but merely a starting point for learning to use it.

What is Stylable?

Stylable is a superset of the CSS language - it introduces additional syntax to CSS to allow us to add features to styling during pre-processing time. It is designed for working with components, variants, themes, and various modern design patterns.

There are different aspects to Stylable, and the tooling and capabilities that it provides:


The Stylable pre-processor works at build-time, meaning that we can use all of its features while writing the code. Its input is a Stylable stylesheet, and its output is valid vanilla CSS. The pre-processing it performs adds the following to CSS:

  • Namespace all parts of CSS that can conflict so that multiple stylesheets can be loaded together safely.
  • A module system to CSS so that individual symbols can be re-used across stylesheets.
  • Template capabilities for creating complex design patterns using variables, mixins, and formatters.
  • The ability to perform external customization of any component or theme by using its Style API through extensions, compositions and overrides.

Type system

We love working with TypeScript and the developer experience that it provides in terms of validations and rich language features.

We aspire for Stylable to be for CSS, what TypeScript is for JavaScript, and so Stylable is in itself a type system, providing interface support for selectors, and reporting syntactic and semantic diagnostics.

Language server

When working in a modern IDE, a language server makes a huge difference in the development experience. For Stylable, we created the Stylable Intelligence VS Code extension to provide a better development experience through completions, definitions, hinting and more.


Pre-processing and language features are not all that Stylable offers. It also includes a set of tools and integrations that help develop, build, and ship better CSS:

  • Stylable CLI - a command line interface to help build, manage, and validate stylesheets for production and CI/CD workflows.
  • Optimization tools - Stylable has a deep awareness of how your stylesheets are used, and can optimize them to shorten names or remove dead code.
  • Bundling - choose one of our supported bundler integrations to bundle your stylesheets for production.

Who is Stylable for?

We modeled Stylable after TypeScript, and like TypeScript, the more complex the project and the more people it involves, the greater the value it provides.

Having said that, even a single developer working on a simple, standalone project could gain a lot of value from Stylable.

Component libraries

Library authors can use Stylable to create reusable components, variants, and themes. It helps organize component and theme styling while controlling the elements and styles that are exposed as public interfaces.


Application creators can use Stylable to compose their own components alongside 3rd party libraries and to theme the final application to their UX and product requirements.

Sounds interesting? Ready to start?
Head on over to the first chapter, where we discuss classes, and what they mean in Stylable.