Simplest Riverpod without Flutter Example

main.dart

import 'dart:async';
import 'package:flutter_riverpod/all.dart';

final container = ProviderContainer(); // declare global ProviderContainer
final countProvider = StateProvider((ref) => 0); // declare providers anywhere

void main() {

  final ProviderSubscription<StateController<int>> subscription = container.listen(countProvider, didChange: (sub) { // listen from container
    print(sub.read().state);
  });

  container.read(countProvider).stream.listen((event) { // or listen from stream
    print(event);
  });

  Timer.periodic(Duration(seconds: 1), (timer) {
    container.read(countProvider).state++; // update state
  });
}