device_unique_id

A reliable device identifier for Android and iOS — using the modern, privacy-respecting approach both platforms actually allow.

Read this first: what's not possible

Neither OS lets a normal app read a true hardware serial number or IMEI. This is an intentional privacy restriction, not a gap in this package:

  • Android 8+: Build.getSerial() requires the READ_PRIVILEGED_PHONE_STATE permission, which only system/OEM-signed apps can hold. Regular apps get back "UNKNOWN".
  • iOS: Apple removed third-party UDID access in iOS 5 (2011) and has never brought it back. Attempting to work around it is an automatic App Store rejection.

If someone tells you their package returns the "real" hardware serial on a normal, non-MDM app — be skeptical of it.

What this package gives you instead

Method Android iOS Survives reinstall?
getPersistentId() EncryptedSharedPreferences UUID Keychain UUID ✅ on iOS, ❌ on Android (removed with app data unless backed up)
getDeviceIdentity().androidId Settings.Secure.ANDROID_ID null ❌ (resets on factory reset)
getDeviceIdentity().identifierForVendor null UIDevice.identifierForVendor ❌ (resets if all vendor's apps are deleted)

Use getPersistentId() for most purposes — licensing checks, fraud signals, per-device analytics. It's the most stable option across both platforms and isn't tied to an OS identifier policy that could change in a future release.

Setup

No manual native setup needed beyond normal Flutter plugin registration — just add the dependency and you're done.

dependencies:
  device_unique_id: ^1.0.0

Android minSdk: 21 (uses AndroidX Security Crypto for encrypted storage). iOS deployment target: 12.0.

Usage

import 'package:device_unique_id/device_unique_id.dart';

// Recommended: the persistent, package-managed UUID.
final id = await DeviceUniqueId.getPersistentId();

// Or get everything this plugin can retrieve:
final identity = await DeviceUniqueId.getDeviceIdentity();
print(identity.persistentId);         // always present
print(identity.androidId);            // null on iOS
print(identity.identifierForVendor);  // null on Android

// Mainly for testing "fresh install" behavior:
await DeviceUniqueId.resetPersistentId();

Choosing the right id for your use case

  • Software licensing / seat limits → getPersistentId(). Stable, under your control, works the same way on both platforms.
  • Fraud/abuse signals → combine getPersistentId() with your server-side account/session data; no client-side id alone is a reliable fraud signal, since a determined user can always reinstall or clear storage.
  • Simple per-install analytics → getPersistentId() is fine, or use a random id generated and stored entirely in your own app if you don't want the native dependency at all.

Project structure

device_unique_id/
├── lib/
│   ├── device_unique_id.dart              # public API
│   └── src/
│       ├── device_identity.dart           # DeviceIdentity model
│       ├── device_unique_id_platform_interface.dart
│       └── method_channel_device_unique_id.dart
├── android/
│   └── src/main/kotlin/.../DeviceUniqueIdPlugin.kt
├── ios/
│   └── Classes/DeviceUniqueIdPlugin.swift
├── example/
│   └── main.dart
└── test/
    └── device_unique_id_test.dart

Contributing

Issues and PRs welcome. Native code changes should be tested on a real device where possible — the Keychain/EncryptedSharedPreferences behavior in particular doesn't fully reflect on simulators/emulators in all cases.

Libraries

device_unique_id