WorkManager schedules deferrable, reliable background tasks. even if app exits or device restarts. OneTimeWorkRequest executes a task once. PeriodicWorkRequest repeats at minimum 15-minute intervals. Worker class implements doWork() with task logic. Constraints control when tasks run: network, charging, idle state. Chaining links work requests in sequence or parallel. Input data passes parameters to workers. Output data returns results from workers. Observing work status with LiveData or Flow. Unique work policies prevent duplicate task creation. Expedited work runs important tasks quickly. Long-running workers show notifications for ongoing tasks. TestWorker provides testing utilities for WorkManager. Initialization configuration customizes WorkManager setup. WorkManager is the recommended solution for deferrable background tasks. It replaces Firebase JobDispatcher, GcmNetworkManager, and JobScheduler. Battery optimization is built-in through constraint-based scheduling. WorkManager handles backward compatibility across API levels. Background task limits in Android 12+ require play catch-up.