Case Study •

Web Pages in Half The Time
Why Microsoft Chose Astro to Build Their Fluent 2 Design System Website

Astro Team

Microsoft is a household name, creator of such popular tools like the Microsoft Office suite. Their product line includes desktop, web, and mobile products e.g. SDKs for Android and iOS. To keep their visual branding consistent across these products, they rely on their design system Fluent 2.

Their Office Engineering and Experiences teams created the first version of Fluent 3-4 years ago. Over the the past 2 years, they have been hard at work on the latest version, Fluent 2. Astro was the best framework for the Fluent 2 website due to performance gains with island architecture. They were looking for something lightweight that fit in with their existing workflow and tools. Astro allowed Microsoft to be agile, helping content editors create and edit content pain-free.

Logos for Microsoft's products including PowerPoint, Excel and more.


Microsoft made several attempts to build their design docs using other frameworks and CMS. They found that these tools were either too rigid, hard to maintain, or migrating was painful. Others did not integrate well with their Figma workflow and the design stories they wanted to tell.

The team took a step back to reassess their priorities and determined that they should focus on the design system and what architecture they actually needed. It turns out their content and designs weren’t suited for a CMS because they had a lot of custom components that they could not reuse. They were unique and required engineering input.

Figma to Markdown workflow.


The team wanted something lightweight and low maintenance on the DevOps side for the Fluent 2 website. This tool would have to support their design system library, which had a React version published. Extensibility was also important i.e. they wanted to be able to add CMS or DocSearch e.g. Algolia later on if they wanted to. Lastly, they wanted to be able to support legacy Storybook iframes to share code examples but be able to migrate off them eventually.

Solution and Implementation

Astro ships zero JavaScript by default, making it perfectly lightweight and performant for Microsoft. Being tool agnostic, Astro also supports other frameworks which meant Microsoft could continue to support their design system library built with React. In the future, they hope to improve the content editing experience by re-adding a CMS. Some of the CMS’ supported by the Astro ecosystem are Storyblok, CloudCannon, and Sanity.

When asked what was the most advantageous part of choosing Astro, Tudor said the following:

“It’s very important to us that Astro is able to generate fully static files. This is very advantageous for us because we want to be protected from multiple things such as DDoS attacks. So, having a product that relies a lot on a back-end service might cause issues. In these times, having a fully static website, and hosting it on Azure, is very advantageous for security and scalability.”

— Tudor Popa, Engineering Manager @ Microsoft (Fluent 2)

Astro also made it possible for Microsoft to continue supporting legacy Storybook iframes until the team was ready to migrate away. This allowed Microsoft to maintain a good experience for external and internal users while they changed their technology stack under the hood.

Microsoft designed and built the new Fluent 2 website with Astro over the course of 10 months, including over 200 pages of new content.


Astro helped the Fluent team build new pages in half the time compared to their previous stack. Astro also helped developers and designers on the team stay aligned with the full power of HTML, CSS, and JavaScript.

Use of the Fluent 2 design system has since been used across many products in the company including Office products, Windows, and Teams. With this setup, Microsoft is able to implement Figma designs for a simple page in 20-30 minutes.

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