When you have configured multiple APIs, you can specify the name of the API as a parameter as the target for an operation:

```dart
Future<void> main() async {
  final operation = Amplify.API.mutate<String>(
    request: GraphQLRequest(
        document: graphQLDocumentString,
        apiName: '[FRIENDLY-NAME-API-WITH-API-KEY]',
    ),
  );
  final response = await operation.response;
  final data = response.data;
  print('data: $data');
}
```