Introduction

Every Flutter app needs some version of the same things: a theming system, responsive layout, form validation, a snackbar, a way to return errors, and a handful of string and date helpers.

Most teams rebuild these each time, slightly differently. Fabrik is that layer, written once and tested properly — focused packages you can adopt one at a time.

Install what you need

There is no meta-package and no required setup. Add the package that solves your problem:

dependencies:
  fabrik_theme: ^1.1.0
  fabrik_layout: ^1.2.0

Nothing here depends on anything else, so adopting one package does not commit you to the rest. Choosing a package maps problems to packages.

A quick taste

Theme your app once:

MaterialApp(
  theme: FabrikTheme.create(
    brightness: Brightness.light,
    colors: AppColors.defaults(),
  ),
  darkTheme: FabrikTheme.create(
    brightness: Brightness.dark,
    colors: AppColors.darkDefaults(),
  ),
);

Then read semantic values anywhere:

Text('Payment failed', style: TextStyle(color: context.colors.error))

final columns = context.layout.value<int>(mobile: 1, tablet: 2, desktop: 3);

Design principles

Semantic over literal. context.colors.error says why a color was chosen; Colors.red only says what it is. Names that carry meaning survive redesigns.

Independent packages. Splitting the toolkit means you never ship code you do not use. A package that only needs Either should not pull in a theming system.

Fail loudly, with a fix. Where a mistake cannot be caught by the type system, it becomes an error that names the solution — an unknown form field lists the valid keys, a missing theme extension names the factory to call.

Testable without widgets. Form state, validation and results are plain Dart objects. You should be able to test business rules without a WidgetTester.

Defaults that work, everything replaceable. Get something on screen first, learn the full API when you need it.

Core concepts covers the patterns that recur across packages.

What Fabrik is not

• Not a state management solution. fabrik_forms handles form state only.
• Not a widget library. No buttons, cards, or dialogs — Fabrik gives you the tokens, the widgets stay yours.
• Not a functional programming framework. fabrik_result ships the parts people use and stops short of typeclasses.

Status

fabrik_theme, fabrik_layout and fabrik_result are at 1.x and follow semantic versioning. fabrik_forms, fabrik_utils and fabrik_snackbar are pre-1.0 and may still change; each change ships with a migration note in the package changelog.

Fabrik is developed in the open at github.com/abhakhand/fabrik. Issues and pull requests are welcome.