Flutter consume API parsing JSON | Consumindo API e convertendo JSON

parse_json.dart

import 'package:http/http.dart' as http;

// T é sua classe
// T is your class

Future<List<T>> getDeputados() async {
  final response = await http.get('url');

  if (response.statusCode == 200) {
    final jsonDecoded =
        json.decode(response.body).cast<Map<String, dynamic>>();
    return jsonDecoded
        .map<T>((x) => T.fromJson(x))
        .toList();
  } else {
    throw Exception('Erro ao carregar T.');
  }
}