All the basic data you need to roll your own analytics payloads

device_service.dart

import 'dart:convert';
import 'dart:io';

import 'package:app/extensions.dart';
import 'package:device_info_plus/device_info_plus.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter_timezone/flutter_timezone.dart';
import 'package:get_it/get_it.dart';
import 'package:package_info_plus/package_info_plus.dart';

Future<void> setupDeviceService() async {
  final x = DeviceService();
  await x.init();
  GetIt.instance.registerSingleton(x);
}

class DeviceService {
  static final _dip = DeviceInfoPlugin();

  Future<void> init() async {
    // Platform
    platform = defaultTargetPlatform.name;
    localeName = Platform.localeName;
    timezone = await FlutterTimezone.getLocalTimezone();

    // Device info
    if (Platform.isIOS) {
      final d = await _dip.iosInfo;
      platform = 'ios';
      deviceId = d.identifierForVendor;
      isPhysicalDevice = d.isPhysicalDevice;
      _deviceData = d.data.toSerializableMap();
    } else if (Platform.isAndroid) {
      final d = await _dip.androidInfo;
      deviceId = d.fingerprint;
      isPhysicalDevice = d.isPhysicalDevice;
      _deviceData = d.data.toSerializableMap();
    } else {
      final d = await _dip.deviceInfo;
      _deviceData = d.data.toSerializableMap();
    }

    // Package info
    final pi = await PackageInfo.fromPlatform();
    version = pi.version;
    buildNumber = pi.buildNumber;
    _packageData = {
      'app_name': pi.appName,
      'build_number': pi.buildNumber,
      'build_signature': pi.buildSignature,
      'installer_store': pi.installerStore,
      'package_name': pi.packageName,
      'version': pi.version,
    };
  }

  // Platform
  String? platform;
  String? localeName;
  String? timezone;

  // Device info
  String? deviceId;
  bool? isPhysicalDevice;
  Map<String, dynamic> _deviceData = {};

  // Package info
  String? version;
  String? buildNumber;
  Map<String, dynamic> _packageData = {};

  Map<String, dynamic>? get analyticsData => {
        ...{
          "platform": platform,
          "localeName": localeName,
          "timezone": timezone,
        }.prefixedWith('platform.'),
        ..._deviceData.prefixedWith("device."),
        ..._packageData.prefixedWith("package."),
      };
}

extension on Map<String, dynamic> {
  Map<String, dynamic> toSerializableMap() {
    return jsonDecode(
      jsonEncode(this, toEncodable: (foo) => foo.toString()),
    );
  }
}

endpoint.dart

ApiResponse<void> userEvent(UserEvent payload) async {
    try {
      await _dio.post<void>(
        "/events/user",
        data: [
          {
            "type": payload.toJson()['type'],
            "payload": payload.toJson(),
          }
        ],
      );
      debugPrint('EVENT: ${payload.toString()}');
      return Result.success(null);
    } on Object {
      return Result.failure(ApiError.serverUnreachable);
    }
  }

extensions.dart

extension StringMapExtensions<V> on Map<String, V> {
  Map<String, dynamic> prefixedWith(String prefix) {
    return {for (final MapEntry(:key, :value) in entries) '$prefix$key': value};
  }
}

user_event.dart

@Freezed(unionKey: "type", unionValueCase: FreezedUnionCase.snake)
class UserEvent with _$UserEvent {
  const factory UserEvent.launchApp() = _UserEventLaunchApp;

  const factory UserEvent.interest(String name, bool interested) =
      _UserEventInterest;

  const factory UserEvent.requestTopic({
    required String topic,
    required String category,
    required String reason,
  }) = _UserEventRequestTopic;

  const factory UserEvent.invalidTopic({
    required String topicId,
  }) = _UserEventInvalidTopic;

  const factory UserEvent.giveFeedback({
    required String feedback,
  }) = _UserEventGiveFeedback;

  const factory UserEvent.appLaunched({
    required String? platform,
    required String? localeName,
    required String? timezone,
    required Environment? environment,
    required bool? kDebugMode,
    required String? deviceId,
    required bool? isPhysicalDevice,
    required String? buildNumber,
    required String? version,
    required Map<String, dynamic>? extra,
  }) = _UserEventAppLaunched;

  factory UserEvent.fromJson(Map<String, Object?> json) =>
      _$UserEventFromJson(json);
}