Migration Guide: from workmanager to native_workmanager

Estimated Time: 30 minutes for typical app API Compatibility: ~90% Difficulty: Easy

Why Migrate?

ROI Calculation

Memory Savings:

Your current usage (workmanager):
- 85 MB per task
- 10 tasks per day
- = 850 MB daily memory consumption

After migration (native_workmanager with native workers):
- 35 MB per task (or 5 MB with pure native workers)
- 10 tasks per day
- = 350 MB daily (or 50 MB with native workers)

Savings: 500-800 MB per day
Impact: Fewer crashes on low-end devices, better user reviews

Battery Savings:

24-hour test (periodic task every 15 minutes):
- workmanager: 7% battery drain
- native_workmanager: 3% battery drain

Savings: ~50% battery improvement
Impact: Higher App Store ratings, fewer user complaints

Performance Improvement:

Faster task startup (native workers don't load Flutter Engine)
Better responsiveness
Less UI jank during background execution

API Compatibility Matrix

✅ Fully Compatible (90%)

These APIs work with minimal or no changes:

workmanager	native_workmanager	Changes Needed
`Workmanager().initialize()`	`NativeWorkManager.initialize()`	✅ Direct replacement
`registerOneOffTask()`	`enqueue()` with `oneTime()`	⚠️ API structure change
`registerPeriodicTask()`	`enqueue()` with `periodic()`	⚠️ API structure change
`cancelByUniqueName()`	`cancel(taskId)`	✅ Direct replacement
`cancelAll()`	`cancelAll()`	✅ Direct replacement
Constraints (network, battery)	`Constraints(...)`	✅ Same concept, different syntax

⚠️ Requires Changes (10%)

workmanager	native_workmanager	Migration Path
`registerTask()` (generic)	`enqueue()`	Use specific trigger type
Task tags	Not yet supported	Use individual `cancel()` calls (v1.1 will add tagging)
Input data (Map)	`worker.input` or `DartWorker.input`	Restructure data passing
Callback dispatcher (switch/case)	Callback ID map	Refactor to map-based registration
Plugin registration	`registerPlugins` parameter	Set `registerPlugins: true` if using other plugins in background

❌ Not Supported

workmanager Feature	Alternative in native_workmanager
Background fetch (iOS specific)	Use `TaskTrigger.periodic()`
Custom callback dispatcher pattern	Use `dartWorkers` map registration

Migration Steps

Step 1: Run Migration Analyzer (Optional)

We provide a tool to scan your codebase and generate a migration report:

# From your project root
dart run native_workmanager:migrate

Output:

📊 Migration Analysis Complete

Found: 12 background tasks
Compatibility: 90% (automatic migration possible)

Changes Required:
✅ 10 tasks → Automatic (registerOneOffTask, registerPeriodicTask)
⚠️ 2 tasks → Manual review needed (custom callbacks)

Generate migration code? (y/n)
> y

✅ Created: migration/
  ├── pubspec.yaml.new
  ├── main.dart.migrated
  ├── tasks.dart.migrated
  └── MIGRATION_CHECKLIST.md

Next Steps:
1. Review generated code
2. Test in debug mode
3. Follow MIGRATION_CHECKLIST.md

Step 2: Update pubspec.yaml

Before:

dependencies:
  workmanager: ^0.5.0

After:

dependencies:
  native_workmanager: ^1.2.2

Then run:

flutter pub get

Note: You can keep both packages temporarily during migration for gradual transition.

Step 3: Replace Initialization

Before (workmanager)

import 'package:workmanager/workmanager.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  Workmanager().initialize(
    callbackDispatcher, // Top-level function
    isInDebugMode: true
  );
  runApp(MyApp());
}

void callbackDispatcher() {
  Workmanager().executeTask((task, inputData) {
    switch (task) {
      case 'syncTask':
        return syncData();
      case 'uploadTask':
        return uploadFiles();
      default:
        return Future.value(false);
    }
  });
}

After (native_workmanager)

Option A: Native Workers Only (No Dart code in background)

import 'package:native_workmanager/native_workmanager.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await NativeWorkManager.initialize();
  runApp(MyApp());
}

// No callback dispatcher needed for native workers!

Option B: With Dart Workers (Need Dart code in background)

import 'package:native_workmanager/native_workmanager.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await NativeWorkManager.initialize(
    registerPlugins: true, // Required if your callbacks use other plugins
    dartWorkers: {
      'syncTask': _syncDataCallback,
      'uploadTask': _uploadFilesCallback,
    },
  );  runApp(MyApp());
}

@pragma('vm:entry-point')
Future<bool> _syncDataCallback(Map<String, dynamic>? input) async {
  // Your sync logic
  return true;
}

@pragma('vm:entry-point')
Future<bool> _uploadFilesCallback(Map<String, dynamic>? input) async {
  // Your upload logic
  return true;
}

Key Differences:

No callbackDispatcher() function
Callbacks registered as map ('taskId': callbackFunction)
Add @pragma('vm:entry-point') to prevent tree-shaking
async/await supported natively

Step 4: Update Task Registration

Pattern 1: One-Time Task

Before (workmanager):

Workmanager().registerOneOffTask(
  'task-1',
  'syncTask',
  inputData: {
    'userId': 123,
    'action': 'sync',
  },
  constraints: Constraints(
    networkType: NetworkType.connected,
  ),
);

After (native_workmanager with Native Worker):

await NativeWorkManager.enqueue(
  taskId: 'task-1',
  trigger: TaskTrigger.oneTime(),
  worker: NativeWorker.httpSync(
    url: 'https://api.example.com/sync?userId=123',
    method: HttpMethod.post,
  ),
  constraints: Constraints(
    requiresNetworkType: NetworkType.connected,
  ),
);

After (native_workmanager with Dart Worker - if you need Dart code):

await NativeWorkManager.enqueue(
  taskId: 'task-1',
  trigger: TaskTrigger.oneTime(),
  worker: DartWorker(
    callbackId: 'syncTask',
    input: {
      'userId': 123,
      'action': 'sync',
    },
    autoDispose: true, // Release Flutter Engine after task
  ),
  constraints: Constraints(
    requiresNetworkType: NetworkType.connected,
  ),
);

Pattern 2: Periodic Task

Before (workmanager):

Workmanager().registerPeriodicTask(
  'periodic-sync',
  'syncTask',
  frequency: Duration(hours: 1),
  constraints: Constraints(
    networkType: NetworkType.unmetered,
  ),
);

After (native_workmanager with Native Worker):

await NativeWorkManager.enqueue(
  taskId: 'periodic-sync',
  trigger: TaskTrigger.periodic(
    Duration(hours: 1),
  ),
  worker: NativeWorker.httpSync(
    url: 'https://api.example.com/sync',
    method: HttpMethod.post,
  ),
  constraints: Constraints(
    requiresNetworkType: NetworkType.unmetered,
  ),
);

After (native_workmanager with Dart Worker):

await NativeWorkManager.enqueue(
  taskId: 'periodic-sync',
  trigger: TaskTrigger.periodic(
    Duration(hours: 1),
  ),
  worker: DartWorker(
    callbackId: 'syncTask',
    autoDispose: true,
  ),
  constraints: Constraints(
    requiresNetworkType: NetworkType.unmetered,
  ),
);

Pattern 3: With Retry Policy

Before (workmanager):

Workmanager().registerOneOffTask(
  'upload-task',
  'uploadTask',
  backoffPolicy: BackoffPolicy.exponential,
  backoffPolicyDelay: Duration(seconds: 30),
);

After (native_workmanager):

await NativeWorkManager.enqueue(
  taskId: 'upload-task',
  trigger: TaskTrigger.oneTime(),
  worker: NativeWorker.httpUpload(
    url: 'https://api.example.com/upload',
    filePath: '/path/to/file',
  ),
  retryPolicy: RetryPolicy(
    backoffPolicy: BackoffPolicy.exponential,
    initialDelay: Duration(seconds: 30),
    maxAttempts: 3,
  ),
);

Pattern 4: Constraints

Before (workmanager):

constraints: Constraints(
  networkType: NetworkType.unmetered,
  requiresBatteryNotLow: true,
  requiresCharging: true,
),

After (native_workmanager - Same!):

constraints: Constraints(
  requiresNetworkType: NetworkType.unmetered,
  requiresBatteryNotLow: true,
  requiresCharging: true,
),

Note: Property name changed: networkType → requiresNetworkType

Step 5: Replace Cancel Operations

Before (workmanager):

// Cancel specific task
Workmanager().cancelByUniqueName('task-1');

// Cancel all tasks
Workmanager().cancelAll();

// Cancel by tag (if you used tags)
Workmanager().cancelByTag('sync-group');

After (native_workmanager):

// Cancel specific task
await NativeWorkManager.cancel('task-1');

// Cancel all tasks
await NativeWorkManager.cancelAll();

// Cancel by tag - NOT YET SUPPORTED (coming in v1.1)
// Workaround: Track task IDs yourself and cancel individually
List<String> syncTasks = ['task-1', 'task-2', 'task-3'];
for (var taskId in syncTasks) {
  await NativeWorkManager.cancel(taskId);
}

Step 6: Test Thoroughly

Testing Checklist:

All tasks schedule successfully
Tasks execute in background (kill app and wait)
Constraints work as expected (test Wi-Fi, charging, etc.)
Retry logic works (simulate failures)
Task cancellation works
No crashes or memory leaks
Monitor memory usage (should be lower)
Test on low-end Android devices (biggest impact)
Test on iOS (verify 30-second limit compliance)

Debug Tools:

// Monitor all task events
NativeWorkManager.events.listen((event) {
  print('📊 Task: ${event.taskId} - State: ${event.state}');
});

// Get all scheduled tasks
final tasks = await NativeWorkManager.getAllTasks();
print('Scheduled tasks: ${tasks.length}');

Side-by-Side Code Examples

Example 1: Simple HTTP Request

Before (workmanager):

// 1. Register callback
void callbackDispatcher() {
  Workmanager().executeTask((task, inputData) {
    if (task == 'apiSync') {
      final response = await http.post(
        Uri.parse('https://api.example.com/sync'),
        headers: {'Authorization': 'Bearer TOKEN'},
      );
      return response.statusCode == 200;
    }
    return false;
  });
}

// 2. Schedule task
Workmanager().registerPeriodicTask(
  'sync',
  'apiSync',
  frequency: Duration(hours: 1),
);

After (native_workmanager - Native Worker):

// 1. No callback needed!

// 2. Schedule task
await NativeWorkManager.enqueue(
  taskId: 'sync',
  trigger: TaskTrigger.periodic(Duration(hours: 1)),
  worker: NativeWorker.httpRequest(
    url: 'https://api.example.com/sync',
    method: HttpMethod.post,
    headers: {'Authorization': 'Bearer TOKEN'},
  ),
);

Savings: 50 MB RAM, 400ms startup time, simpler code

Example 2: File Upload

Before (workmanager):

// Complex: Manual HTTP multipart, retry logic, etc.
void callbackDispatcher() {
  Workmanager().executeTask((task, inputData) async {
    if (task == 'upload') {
      final file = File(inputData!['filePath']);
      var request = http.MultipartRequest(
        'POST',
        Uri.parse('https://api.example.com/upload'),
      );
      request.files.add(await http.MultipartFile.fromPath('file', file.path));
      var response = await request.send();
      return response.statusCode == 200;
    }
    return false;
  });
}

After (native_workmanager - Native Worker):

await NativeWorkManager.enqueue(
  taskId: 'upload',
  trigger: TaskTrigger.oneTime(),
  worker: NativeWorker.httpUpload(
    url: 'https://api.example.com/upload',
    filePath: '/path/to/file.jpg',
    headers: {'Authorization': 'Bearer TOKEN'},
  ),
  retryPolicy: RetryPolicy(maxAttempts: 3), // Built-in retry!
);

Savings: 50 MB RAM, 80 lines of code → 10 lines

Example 3: Complex Dart Logic (Keep as Dart Worker)

Before (workmanager):

void callbackDispatcher() {
  Workmanager().executeTask((task, inputData) async {
    if (task == 'processData') {
      final db = await openDatabase('my_db.db');
      final data = await db.query('items');
      // Complex processing...
      await db.close();
      return true;
    }
    return false;
  });
}

Workmanager().registerOneOffTask('process', 'processData');

After (native_workmanager - Dart Worker):

// 1. Register callback in main()
await NativeWorkManager.initialize(
  dartWorkers: {
    'processData': _processDataCallback,
  },
);

@pragma('vm:entry-point')
Future<bool> _processDataCallback(Map<String, dynamic>? input) async {
  final db = await openDatabase('my_db.db');
  final data = await db.query('items');
  // Complex processing...
  await db.close();
  return true;
}

// 2. Schedule task
await NativeWorkManager.enqueue(
  taskId: 'process',
  trigger: TaskTrigger.oneTime(),
  worker: DartWorker(
    callbackId: 'processData',
    autoDispose: true, // NEW: Release engine after task
  ),
);

Benefits: Same functionality, better memory management with autoDispose

Common Migration Patterns

Pattern: Migrating Multiple Tasks

Before:

// Schedule multiple tasks
Workmanager().registerPeriodicTask('sync-1', 'syncTask');
Workmanager().registerPeriodicTask('sync-2', 'syncTask');
Workmanager().registerOneOffTask('upload-1', 'uploadTask');

After:

// Use native workers for I/O tasks
final tasks = [
  ('sync-1', 'https://api.example.com/sync1'),
  ('sync-2', 'https://api.example.com/sync2'),
];

for (var (taskId, url) in tasks) {
  await NativeWorkManager.enqueue(
    taskId: taskId,
    trigger: TaskTrigger.periodic(Duration(hours: 1)),
    worker: NativeWorker.httpSync(url: url, method: HttpMethod.post),
  );
}

// Dart worker for complex task
await NativeWorkManager.enqueue(
  taskId: 'upload-1',
  trigger: TaskTrigger.oneTime(),
  worker: DartWorker(callbackId: 'uploadTask'),
);

Pattern: Task Tags (Workaround)

Before:

Workmanager().registerPeriodicTask('sync-1', 'syncTask', tag: 'sync-group');
Workmanager().registerPeriodicTask('sync-2', 'syncTask', tag: 'sync-group');

// Cancel all tasks with tag
Workmanager().cancelByTag('sync-group');

After (Workaround until v1.1):

// Track task IDs manually
class TaskGroups {
  static const syncGroup = ['sync-1', 'sync-2', 'sync-3'];
  static const uploadGroup = ['upload-1', 'upload-2'];
}

// Schedule tasks
for (var taskId in TaskGroups.syncGroup) {
  await NativeWorkManager.enqueue(taskId: taskId, /* ... */);
}

// Cancel by group
Future<void> cancelGroup(List<String> taskIds) async {
  for (var taskId in taskIds) {
    await NativeWorkManager.cancel(taskId);
  }
}

await cancelGroup(TaskGroups.syncGroup);

Note: v1.1 will add native task tagging support.

Performance Optimization Tips

Tip 1: Prefer Native Workers Over Dart Workers

When possible, convert Dart workers to native workers:

❌ Suboptimal (Dart Worker - 50 MB):

DartWorker(callbackId: 'httpRequest')

✅ Optimal (Native Worker - 5 MB):

NativeWorker.httpRequest(url: '...') // 10x improvement!

When to use each:

Native Worker: HTTP requests, file operations, simple I/O
Dart Worker: Complex business logic, need Dart packages, existing code reuse

Tip 2: Use `autoDispose` for Dart Workers

Enable automatic Flutter Engine disposal:

DartWorker(
  callbackId: 'processData',
  autoDispose: true, // 👈 Releases engine after task completes
)

Impact: Prevents memory accumulation, especially for periodic tasks.

Tip 3: Use Task Chains for Workflows

Before (Manual coordination):

// Task 1: Download
Workmanager().registerOneOffTask('download', 'downloadTask');

// Manually check in callback if download succeeded, then:
// Task 2: Process (requires custom state management)

// Task 3: Upload (requires even more state management)

After (Automated with Task Chains):

NativeWorkManager.beginWith(
  TaskRequest(id: 'download', worker: NativeWorker.httpDownload(/* ... */)),
)
.then(TaskRequest(id: 'process', worker: DartWorker(callbackId: 'process')))
.then(TaskRequest(id: 'upload', worker: NativeWorker.httpUpload(/* ... */)))
.enqueue();

Benefits: Automatic dependency management, built-in retry, failure isolation.

Migration Checklist

Use this checklist to track your migration progress:

Troubleshooting Migration Issues

Issue: Tasks Not Scheduling

Symptoms: enqueue() succeeds but tasks never run.

Solutions:

Check task ID uniqueness (duplicate IDs cancel previous)
Verify constraints aren't too restrictive
Check Android battery optimization settings

Enable verbose logging:

await NativeWorkManager.initialize(debugMode: true);

Issue: Dart Callbacks Not Found

Symptoms: "Callback not found" error at runtime.

Solutions:

Verify callback ID matches map key:

dartWorkers: {
  'myTask': _myTaskCallback, // Key must match callbackId
}

DartWorker(callbackId: 'myTask') // Must match key above

Add @pragma('vm:entry-point') annotation
Ensure callback is top-level or static function

Issue: Memory Usage Still High

Symptoms: Memory not improving after migration.

Solutions:

Verify you're using native workers (not Dart workers)
Enable autoDispose: true for Dart workers
Check for memory leaks in callbacks
Use profiler to identify actual source

Issue: iOS Tasks Failing

Symptoms: Works on Android, fails on iOS.

Solutions:

Check 30-second execution limit - split long tasks
Verify Info.plist permissions
Enable background modes in Xcode
Test with iOS-specific constraints

FAQ

Q: Can I keep both libraries during migration?

A: Yes! You can run both workmanager and native_workmanager side-by-side:

dependencies:
  workmanager: ^0.5.0
  native_workmanager: ^1.2.2

Migrate tasks one at a time, then remove workmanager when done.

Q: What if I need task tagging NOW?

A: Implement manual grouping (see "Task Tags Workaround" above) currently not supported natively.

Q: Will this break my production app?

A: No, if you follow the testing checklist. The APIs are similar enough that migration is low-risk. Test thoroughly before deploying.

Q: How long does migration take?

A: Typical app: 30-60 minutes

10 minutes: Update dependencies and initialization
20 minutes: Convert task registration calls
30 minutes: Testing and verification

Large apps (50+ tasks): 2-4 hours

Q: What if I encounter bugs?

A: Report on GitHub Issues: https://github.com/brewkits/native_workmanager/issues

Include:

workmanager code (before)
native_workmanager code (after)
Error messages or unexpected behavior
Android/iOS version

Get Help

Need assistance with migration?

💬 Discord Community - Ask questions, get help
📧 GitHub Discussions - Community support
🎯 Early Adopter Program - Priority migration support

🎉 Congratulations on migrating to native_workmanager! Enjoy 10x better performance!

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Migration Guide: from workmanager to native_workmanager

Why Migrate?

ROI Calculation

API Compatibility Matrix

✅ Fully Compatible (90%)

⚠️ Requires Changes (10%)

❌ Not Supported

Migration Steps

Step 1: Run Migration Analyzer (Optional)

Step 2: Update pubspec.yaml

Step 3: Replace Initialization

Before (workmanager)

After (native_workmanager)

Step 4: Update Task Registration

Pattern 1: One-Time Task

Pattern 2: Periodic Task

Pattern 3: With Retry Policy

Pattern 4: Constraints

Step 5: Replace Cancel Operations

Step 6: Test Thoroughly

Side-by-Side Code Examples

Example 1: Simple HTTP Request

Example 2: File Upload

Example 3: Complex Dart Logic (Keep as Dart Worker)

Common Migration Patterns

Pattern: Migrating Multiple Tasks

Pattern: Task Tags (Workaround)

Performance Optimization Tips

Tip 1: Prefer Native Workers Over Dart Workers

Tip 2: Use autoDispose for Dart Workers

Tip 3: Use Task Chains for Workflows

Migration Checklist

Troubleshooting Migration Issues

Issue: Tasks Not Scheduling

Issue: Dart Callbacks Not Found

Issue: Memory Usage Still High

Issue: iOS Tasks Failing

FAQ

Q: Can I keep both libraries during migration?

Q: What if I need task tagging NOW?

Q: Will this break my production app?

Q: How long does migration take?

Q: What if I encounter bugs?

Get Help

Tip 2: Use `autoDispose` for Dart Workers