The adaptive interface system for modern web experiences.





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License: MIT lerna TypeScript code style: prettier

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This is the FAST monorepo, containing web component packages, tools, examples, and documentation. FAST tech can be used à la carte or as a suite to build enterprise-grade websites, applications, components, design systems, and more.

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FAST is a collection of technologies built on Web Components and modern Web Standards, designed to help you efficiently tackle some of the most common challenges in website and application design and development.


  • Create reusable UI components based on web component standards.
  • Use our standard library of pre-built web components in your apps.
  • Choose between two adaptive design systems: Fluent Design and FAST Frame.
  • Build your own design system without re-implementing component logic.
  • Integrate with any front-end framework or build system.

For an in-depth explanation of FAST see our docs introduction.



License: MIT npm version

The @microsoft/fast-element library is a lightweight means to easily build performant, memory-efficient, standards-compliant Web Components. FAST Elements work in every major browser and can be used in combination with any front-end framework or even without a framework. To get up and running with @microsoft/fast-element see the Getting Started guide.


License: MIT npm version

The @microsoft/fast-foundation package is a library of Web Component classes, templates, and other utilities intended to be composed into registered Web Components by design systems (e.g. Fluent Design, Material Design, etc.). The exports of this package can generally be thought of as un-styled base components that implement semantic and accessible markup and behavior.

This package does not export Web Components registered as custom elements - it exports parts and pieces intended to be composed into Web Components, allowing you to implement your own design language by simply applying CSS styles and behaviors without having to write all the JavaScript that's involved in building production-quality component implementations.


License: MIT npm version

@microsoft/fast-components is a library of Web Components that composes the exports of @microsoft/fast-foundation with stylesheets aligning to the FAST Frame design system. This composition step registers a custom element. See the quick start to get started using the components.


License: MIT npm version

@fluentui/web-components is a library of Web Components that composes @microsoft/fast-foundation. @fluentui/web-components makes use of different stylesheets and may include components that specifically support Microsoft's Fluent design language.

The source for @fluentui/web-components is hosted in the Fluent UI monorepo.

Component Explorer

Launch our Component Explorer to experience our FAST Components and development tools.

Getting Started

We hope you're excited by the possibilities that FAST presents. But, you may be wondering where to start. Here are a few statements that describe various members of our community. We recommend that you pick the statement you most identify with and follow the links where they lead. You can always come back and explore another topic at any time.

Joining the Community

Looking to get answers to questions or engage with us in realtime? Our community is most active on Discord. Submit requests and issues on GitHub, or join us by contributing on some good first issues via GitHub.

Get started here with the Contributor Guide.

We look forward to building an amazing open source community with you!

Features & benefits


There are a million and one great ways to build your next website or application. To support the technologies you choose, creating unopinionated code is at the center of every decision we make in FAST.

This principle of being unopinionated manifests in several important ways including:

  • A flat component architecture that lets you compose what you need without struggling with rigid patterns and complex objects.
  • Separating base components from styles and design systems to support multiple implementations without re-writing or duplicating styles. Use the design system to customize existing styled components, or build your own styles, with your design system, without having to rebuild or duplicate the base components.
  • Framework agnostic tooling that lets you use our development tools with any view framework.
  • The ability to replace almost any FAST package with your package of choice. Get started with our animation package and add more as you need them. Alternatively, use our suite of packages to build your next project from the ground up; it's your call.

UI development and style guide tools

When developing components and views, excellent development tooling can make all the difference. FAST offers development and style guide tools that work with FAST components, components from other frameworks, or your components.

Try out component properties with an auto-generated property UI, get a live preview of the code based on any property’s configuration, preview localization (RTL/LTR) and themes, and preview component compositing with a transparency grid.

Also, we built FAST development tools from re-usable packages, so if you have special needs, you can build your tools from the same shared libraries.

Bring your design system

Widely available design systems from companies like Microsoft (Fluent), Google (Material), or Salesforce (Lightning) are useful when it is essential to align with a platform or take advantage of a polished system at low cost, but many companies have a design system of their own, and some may have multiple design systems or variations.

Because FAST has abstracted base components from their style, you get a head start on your design system by building on top of tried and true base components and style libraries like our offerings for color, animation, and elevation.


  • Join the community and chat with us in real-time on Discord.
  • Submit requests and issues on GitHub.
  • Contribute by helping out on some of our recommended first issues on GitHub.

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