lib_repository.dart

//This file is in `./lib` folder

import 'package:http/http.dart' show Client;

import '.env.dart';

class Repository {
  final String _baseUrl = environment.baseUrl;

  Client _client;

  DebtorRepository() {
    this._client = Client();
  }
  
  // For simplicity's sake we will not deal with json encoding/decoding
  Future<any> info(String token) async {
    return await this._client.get('$_baseUrl/info');
  }
}

setup_env.sh

#!/bin/bash
dart tool/env.dart

tool_env.dart

//This file is in `./tool` folder

import 'dart:convert';
import 'dart:io';

Future<void> main() async {
  final config = {
    'baseUrl': Platform.environment['APP_BASE_URL'],
    'credentials': Platform.environment['APP_CREDENTIALS'],
  };

  final filename = 'lib/.env.dart';
  File(filename).writeAsString('final environment = ${json.encode(config)};');
}

Hi @esarbanis do you have any sample project for this?