Paris is Slingshot's React design system, meant to work universally across server and client components. It's a collection of reusable components, design tokens, and guidelines for building consistent, accessible, and performant user interfaces.
Paris ships as precompiled ESM with extracted CSS and TypeScript declarations. Each component is a separate entry point, so you import only what you need and tree-shaking keeps your bundle small. Because it's prebuilt, Paris works out of the box in any modern React setup — Next.js (including the App Router and Server Components) and Vite React — with no special bundler configuration and no Sass toolchain required.
Paris 1.x styling is heavily inspired by Uber's Base Web, which we previously used in our production apps. We built Paris to move away from Styletron and CSS-in-JS, since we're now largely working with React 19, RSC, and the Next.js app directory.
As of v0.24, Paris ships precompiled — so you can remove transpilePackages: ['paris'] and the sass dependency, and switch your global-styles import to paris/theme/global.css. Component import paths are unchanged. (Use ^0.24.1 or newer — 0.24.0 had a CSS packaging bug that left components unstyled.)
The easiest way to upgrade is to hand it to your coding agent. Copy the prompt below into Claude Code, Cursor, or any agent working in your repo:
Upgrade this project's
parisdependency to^0.24.1(or newer). Follow the official migration guide at https://paris.slingshot.fm/migrate-0.24.md carefully and step by step — fetch and read the whole guide first, make only the changes it describes, and run the project's build/typecheck at the end to confirm everything passes. Report exactly what you changed.
Prefer to do it by hand? The same guide is here: Migration guide → v0.24.
First, install Paris in your project:
pnpm i paris
# or
yarn add paris
# or
npm i parisMake sure your tsconfig module resolution is set to nodenext, node16, or bundler to support paris imports:
{
"compilerOptions": {
"moduleResolution": "bundler"
}
}That's all the bundler setup required. Because Paris is prebuilt, there's no transpilePackages to add and no sass dependency to install — the component CSS is already extracted and auto-imported alongside each component. (If you're upgrading from an older Paris that required these, you can now remove them.)
Paris uses pte (our theming engine) for powering theming and initial styles through CSS variables. You can use generateCSS or generateThemeInjection from paris/theme to generate the CSS variables and inject them into your app through either a style or script tag in your document head respectively. Either method supports SSR and server components, since the initial theme is static.
Additionally, you need to import the precompiled static global styles from paris/theme/global.css.
Paris also relies on CSS Container Queries for responsive changes on certain elements, like the Tabs component when kind = auto. Adding the Google polyfill for Container Queries is recommended to ensure legacy browser support:
// Use the `Script` component instead in Next.js
<script src="https://cdn.jsdelivr.net/npm/container-query-polyfill@1/dist/container-query-polyfill.modern.js" />For example, with the Next.js 13 app directory, you can do all of this in your root layout.tsx file:
// app/layout.tsx
import { generateCSS, generateThemeInjection, theme } from 'paris/theme';
// Import Paris's static global styling
import 'paris/theme/global.css';
export default function RootLayout({
children,
}: {
children: React.ReactNode
}) {
return (
<html lang="en">
<head>
{/* Using a `style` tag (MUST have the id `pte-vars` and be in the document head) */}
<style
id="pte-vars"
dangerouslySetInnerHTML={{
__html: generateCSS(theme),
}}
/>
{/* Or, use a `script` tag (can be located anywhere, should be loaded as early as possible to avoid an unstyled flash) */}
<script
dangerouslySetInnerHTML={{
__html: generateThemeInjection(theme),
}}
/>
</head>
{/* Set the class "paris-container" to your root layout container */}
<body className="paris-container">
{children}
<Script src="https://cdn.jsdelivr.net/npm/container-query-polyfill@1/dist/container-query-polyfill.modern.js" />
</body>
</html>
);
}That's it! You can now import any component from Paris:
import { Button } from 'paris/button';
const App = () => (
<Button>Click me</Button>
);This works out of the box with Next.js (App Router and Server Components) and Vite React — components ship as compiled ESM with their styles already bundled, so no extra bundler or Sass configuration is needed.