This example project tested how we keep secure the data in Flutter, example, api key(s).

1. Create the .env inside the main directory.
2. Create the env.dart file.
3. For static variable static String apiKey = _Env and run the new command (the old one deprecated) "dart run build_runner build" or dart run build_runner build --delete-conflicting-outputs.
4. Generated.
5. Add the Key static String apiKey = _Env.apiKey.

For this example keeps the files with dummy/tested api key but for real project you have to add them in gitignore file.

dart run build_runner build or dart run build_runner build --delete-conflicting-outputs

Flutter SDK version: 3.22.2
Dart Version: 3.4.3

https://pub.dev/packages/envied
https://medium.com/@r1n1os/securing-sensitive-data-in-flutter-d0a8e060a11e
https://github.com/r1n1os/Secure-Sensitive-Data-Example