Pub Package


Build your app config via code generation from .json files. Type-Safe and no unnecessary IO/Parsing on app-startup!

Note: this is an experimental library. Use with caution!


  • Avoid storing your configuration in dart files
  • Avoid reading config files from disk and parsing them at app start
  • Type safe
  • Supports String, bool, int, double and Enums

How to use

Add to your devDependencies (see example):

  build_runner: <version>
  config_builder: <version>

Define your configuration model:

part 'config.g.dart'; //use the <filename>.g.dart, where <filename> is the name of this dart file

  ConfigFile(configName: "devConfig", path: ""),
  ConfigFile(configName: "testConfig", path: "config.test.json"),
class Config{
  final String name;
  final int value;
  final Environment environment;

  const Config({, this.value, this.environment});

Make sure the config-class has a const constructor with exclusively named parameters. The generated code will assume that such a constructor exists.

Add your configuration-json file:

  "name" : "devApp",
  "value": 1,
  "environment" : "Dev"

Run the code generation via

flutter packages pub run build_runner build

Now you can access your config object for example via different entry points in your app:

import 'config.dart';

void main() => printConfig(devConfig);


import 'config.dart';

void main() => printConfig(testConfig);

known issues

  • build_runner caches the result and won't collect changes in your config files if none of your source files changed since the last build I'll look into how this can be fixes. In the meantime, just add a new line somewhere in your config.dart file to force a new build.