Head-to-Head: Primer CSS vs Fela Analysis


v21.0.9(22 days 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


v12.2.1(11 months ago)

This package is actively maintained.Types definitions are bundled with the npm packageNumber of direct dependencies: 5Monthly npm downloads

Fela is a powerful and flexible CSS-in-JS library for building scalable and maintainable user interfaces. It allows you to write your styles in JavaScript using a functional approach, providing a declarative and composable way to define styles for your components. Fela offers a wide range of features including dynamic styling, theming, media queries, and CSS animations.

Alternatives: styled-components, emotion, aphrodite

Tags: javascriptcss-in-jsstylinguser-interfaceperformance



Both @primer/css and Fela are popular npm packages in the CSS-in-JS ecosystem. However, @primer/css is specifically built and maintained by GitHub's Primer team, which gives it a significant edge in popularity, especially within the GitHub community.


In terms of bundle size, @primer/css is relatively lightweight as it focuses on providing utility classes and components for building GitHub-styled applications. Fela, on the other hand, is a more feature-rich CSS-in-JS solution, and its bundle size may be larger due to the additional functionality it offers.


@primer/css follows a conventional CSS approach, where you define utility classes and use them in your components. It offers a comprehensive set of utility classes and components for building consistent and responsive user interfaces. Fela, on the other hand, is a more dynamic CSS-in-JS solution that generates unique class names for each component and manages the styles using a JavaScript API. It provides advanced features like dynamic theming, media queries, and complex style compositions.


Both @primer/css and Fela can be integrated with React applications. However, @primer/css is specifically designed to work with GitHub's Primer framework and may be more suitable for GitHub-styled projects. Fela, on the other hand, is framework-agnostic and can be used with any JavaScript framework or library.

Developer Experience

The developer experience with @primer/css is streamlined and intuitive, as it provides a well-structured and documented set of utility classes and components. Fela, being a more powerful CSS-in-JS solution, offers advanced features but may have a steeper learning curve. It provides a flexible API and allows for more programmatic control over styles.

Community Support

Both @primer/css and Fela have active communities and are regularly maintained. However, @primer/css benefits from being an official library maintained by GitHub, which ensures sustained support and updates. Fela has a dedicated community and offers extensive documentation and support resources.