if more than one api call on flutter and some complex design then it wil be take time?

The speed of API calls depends on several factors,

1. Server Performance: Response time, database optimization, and load handling.
2. Network Latency: Internet speed and server location.
3. Payload Size: Smaller payloads are faster.
4. Concurrency: Parallel calls are faster for independent APIs.

Optimization Tips

1. Use Future.wait for parallel calls.
2. Fetch only necessary data (e.g., pagination, filtering).

To measure the speed you can do like this:

void measureApiSpeed() async {
  final start = DateTime.now();
  await fetchApi(); // Replace with your API call
  print('Time taken: ${DateTime.now().difference(start).inMilliseconds}ms');
}

For parellel API calls use Future.wait

class OrdersPage extends StatelessWidget {
  const OrdersPage({super.key});

  Future<String> fetchUserData() async {
    await Future.delayed(const Duration(seconds: 2)); // Simulate API delay
    return 'User Data';
  }

  Future<String> fetchOrderDetails() async {
    await Future.delayed(const Duration(seconds: 3)); // Simulate API delay
    return 'Order Details';
  }

  Future<String> fetchNotifications() async {
    await Future.delayed(const Duration(seconds: 1)); // Simulate API delay
    return 'Notifications';
  }

  Future<List<String>> fetchAllData() async {
    try {
      // Start all API calls concurrently
      final results = await Future.wait([
        fetchUserData(),
        fetchOrderDetails(),
        fetchNotifications(),
      ]);

      return results;
    } catch (error) {
      throw 'Error fetching data: $error';
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: FutureBuilder(
          future: fetchAllData(),
          builder: (context, snapshot) {
            if (snapshot.hasData) {
              final data = snapshot.data as List<String>;
              return Column(
                children: [
                  Text(data[0]),
                  Text(data[1]),
                  Text(data[2]),
                ],
              );
            } else if (snapshot.hasError) {
              return Center(child: Text(snapshot.error.toString()));
            } else {
              return const Center(child: CircularProgressIndicator());
            }
          }),
    );
  }
}