fossui

Every Flutter app looks like Material, because Material is what you get for free. For the last few months we've been building an alternative.

It's called fossui: a small, open-source Flutter UI kit for the apps that would rather not look like every other Flutter app.

What it is

  • 30+ components, one dependency, no icon package
  • Framework-agnostic: it reads its own theme, so it drops into a MaterialApp, a CupertinoApp, or a bare WidgetsApp
  • A neutral look with superellipse (squircle) corners, light and dark out of the box
  • Built for the AI era: an MCP server and skills, so coding agents write it with the right variants instead of guessing the API

Why

Most Flutter component libraries ask you to buy into their world, wrap your app, or drive ThemeData directly. We wanted the opposite: components that respect a theme you already control, whether or not you're on MaterialApp. Retheme once at the root, and the whole set follows.

What ships around it

  • Docs at fossui.org, with a rendered light and dark preview for every component
  • A playground and theme builder at play.fossui.org, recolor the whole set live and copy the theme out
  • An MCP server so coding agents scaffold and theme fossui correctly on the first try

Where it stands

Young, mobile-first, and built by a team of two. Web and desktop compile and should work, but they're less exercised than mobile.

What would make or break fossui for your next Flutter app?

Site: https://fossui.org
Package: https://pub.dev/packages/fossui
Source: https://github.com/fossui/fossui