What is a REST API, and how does a Flutter app typically genuinely interact with one using standard HTTP methods such as GET, POST, PUT, and DELETE?

A REST API exposes a genuinely specific set of endpoints, each identified by its own particular URL, that a client such as your Flutter app can properly interact with using standard HTTP methods, where GET retrieves genuinely existing data, POST creates a brand new resource, PUT properly updates an already existing resource, and DELETE properly removes a given resource, and a Flutter app typically uses either the http or Dio package to actually make these particular requests, then properly parses the returned JSON response into its own genuinely usable Dart model objects.

final response = await http.get(Uri.parse('https://api.example.com/orders'));
final orders = jsonDecode(response.body) as List;