Head-to-Head: Primer CSS vs JSS Analysis


v21.1.1(1 day ago)

This package is actively maintained.The package doesn't have any types definitionsNumber of direct dependencies: 2Monthly npm downloads

@primer/css is a utility-first CSS library that provides a set of pre-defined classes to help you style your HTML elements. It's created and maintained by GitHub's design system team and follows the Primer design system. @primer/css offers a robust set of styling options for typography, layout, color, and more.

Alternatives: Bootstrap, Tailwind CSS, Bulma

Tags: cssdesigngithubutility-firstlightweight


v10.10.0(10 months ago)

This package is actively maintained.Types definitions are bundled with the npm packageNumber of direct dependencies: 4Monthly npm downloads

JSS is a powerful and flexible JavaScript library for styling your applications. It provides a way to write CSS styles in JavaScript, allowing you to create dynamic and reusable stylesheets. With JSS, you can define styles as JavaScript objects or use CSS syntax with the help of a CSS-in-JS compiler.

Alternatives: styled-components, emotion, aphrodite

Tags: javascriptstylingcss-in-jsdynamic-stylescomponent-styling



@primer/css is the official CSS utility library from GitHub's Primer design system, and it has gained popularity within the GitHub community. On the other hand, jss is a popular JavaScript CSS-in-JS library widely used in the React ecosystem.

Use Case

@primer/css is primarily focused on providing ready-to-use utility classes and CSS styles to quickly style web applications. It is more suitable for projects that want to leverage a pre-defined design system and maintain consistent styles. jss, on the other hand, is a JavaScript CSS-in-JS library that allows you to create and manage styles programmatically. It is better suited for projects that require dynamic styling or custom theming.


@primer/css is designed to be used with any CSS-in-JS library or traditional CSS workflow. It provides a set of pre-built CSS classes and utility functions that can be easily integrated into your project. jss, on the other hand, is a standalone JavaScript library that works well with React and other frameworks. It provides an API to define and manage styles directly in your JavaScript code.


@primer/css is optimized for performance and has a small footprint. It leverages atomic CSS and functional CSS principles to generate minimal and reusable styles. jss, on the other hand, adds a runtime CSS generation layer which can impact performance compared to static CSS bundling. However, depending on the use case, the performance difference may not be significant.

Developer Experience

@primer/css provides a consistent set of utility classes and styles, making it easy to apply styles without writing custom CSS. It requires minimal configuration and is a good choice for developers who prefer a plug-and-play solution. jss, on the other hand, offers more flexibility but requires writing and managing styles programmatically. It has a bit steeper learning curve but provides greater control and customization options.

Community Support

Both packages have active communities and are well-maintained. However, @primer/css benefits from being part of the GitHub ecosystem and has a larger community support due to its association with the popular Primer design system. jss also has a dedicated community and is widely used in the React community, with many plugins and integrations available.