Front-end

The fastest and easiest way to check, copy and edit CSS. Goodbye to "Inspect Element" — Visualize the CSS of any element you hover over, instantly, and copy its entire rules with a single click.

A collection of CSS3 powered hover effects to be applied to links, buttons, logos, SVG, featured images and so on. Easily apply to your own elements, modify or just use for inspiration. Available in CSS, Sass, and LESS.

Simple. Fast. Web Components. Lit is a simple library for building fast, lightweight web components. At Lit's core is a boilerplate-killing component base class that provides reactive state, scoped styles, and a declarative template system that's tiny, fast and expressive.

Materialize is a modern responsive CSS framework based on Material Design by Google.

Completely unstyled, fully accessible UI components, designed to integrate beautifully with Tailwind CSS.

Design System Fundamentals. Magnifying glass. Component Blueprints. Ready-to-use HTML and CSS UI elements provide the foundation for Salesforce experience

Gatsby is a React-based open source framework with performance, scalability and security built-in. Collaborate, build and deploy 1000x faster with Gatsby Cloud.

Bourbon is a library of pure Sass mixins and functions that are designed to make you a more efficient style sheet author.

Foundation is a family of responsive front-end frameworks that make it easy to design beautiful responsive websites, apps and emails that look amazing on any device. Foundation is semantic, readable, flexible, and completely customizable.

A design element gallery for web designers and web developers. Find snippets using HTML, CSS, Javascript, jQuery, and Bootstrap.

The world’s most popular front-end open source toolkit, featuring Sass variables and mixins, responsive grid system, extensive prebuilt components, and powerful JavaScript plugins.

Pixel perfect mobile UI components built with Tailwind CSS With iOS and Material Design components for React, Vue & Svelte

Evergreen is a React UI Framework for building ambitious products on the web. Made by Segment in San Francisco, CA.

Ionic Framework's app development platform builds amazing cross-platform mobile, web, and desktop apps all with one shared code base and open-web standards.

MUI provides a robust, customizable, and accessible library of foundational and advanced components, enabling you to build your design system and develop React applications faster.

Build Web Apps With HTML. Remake is a web app framework that makes it possible to ship a product faster than ever.

Stimulus is a JavaScript framework with modest ambitions. It doesn’t seek to take over your entire front-end—in fact, it’s not concerned with rendering HTML at all. Instead, it’s designed to augment your HTML with just enough behavior to make it shine.

The Progressive JavaScript Framework. An approachable, performant and versatile framework for building web user interfaces.

A utility-first CSS framework packed with classes like flex, pt-4, text-center and rotate-90 that can be composed to build any design, directly in your markup.

Free and open source framework to develop mobile, desktop or web apps with native look and feel. It is also an indispensable prototyping tool to show working app prototype as soon as possible.

Theme UI is a library for creating themeable user interfaces based on constraint-based design principles. Build custom component libraries, design systems, web applications, Gatsby themes, and more with a flexible API for best-in-class developer ergonomics.

Storybook is an open source tool for building UI components and pages in isolation. It streamlines UI development, testing, and documentation.

World's first Design-System-as-a-Service platform. Build, maintain and deliver your design system to all your product teams, blazing fast

Specify helps you unify your brand identity by collecting, storing and distributing design tokens and assets for your design system — automatically.

Formspree is a form backend, API, and email service for HTML & JavaScript forms. It’s the simplest way to embed custom contact us forms, order forms, or email capture forms on your static website.

Drag and drop form building

Collect submissions, receive emails and connect your HTML form with popular apps. Perfect for JAMStack and API-driven static websites. No form backend

The Workday Canvas Design System provides designers and developers with tools to create exceptional experiences.

Assets for building high-quality, consistent user experiences at Thumbtack.

The design system that powers GitHub. We love it so much, we chose to open-source it to allow the community to design and build their own projects with Primer.