Background Work Boundaries

Use the smallest background mechanism that matches the user promise.

Work	Use	Do Not Use
In-screen async work	Coroutine in `viewModelScope` or repository scope	WorkManager
Reliable deferrable work	WorkManager	Raw threads or one-off coroutines
Exact alarm	AlarmManager, only when exact timing is truly required	WorkManager for clock-precise promises
User-visible long-running work	Foreground service or long-running Worker with notification	Silent background loops
Incoming platform event	Broadcast receiver, then hand off quickly	Heavy parsing directly in receiver

WorkManager Fits

Use WorkManager when the work should survive app exit or device reboot:

export backup after user request
periodic local cleanup
deferred sync when network is available
retryable upload of user-approved diagnostics
post-import processing that can resume later

WorkManager gives you constraints, unique work, chaining, retries/backoff, and persistent scheduling.

WorkManager Does Not Fit

Do not use WorkManager for:

filtering a list while the screen is visible
loading initial UI state from a repository
parsing one SMS synchronously during onboarding
exact alarm-clock behavior
continuous background tracking with no user-visible reason

Unique Work Pattern

Use unique names for recurring or replaceable jobs:

val request = OneTimeWorkRequestBuilder<ExportBackupWorker>()
    .setConstraints(
        Constraints.Builder()
            .setRequiresBatteryNotLow(true)
            .build(),
    )
    .build()

WorkManager.getInstance(context).enqueueUniqueWork(
    "export-backup",
    ExistingWorkPolicy.REPLACE,
    request,
)

Worker Boundary

A worker should read durable state, perform one job, and return a clear result.

class ExportBackupWorker(
    context: Context,
    params: WorkerParameters,
) : CoroutineWorker(context, params) {
    override suspend fun doWork(): Result {
        return try {
            // Read from repository or database and write the export.
            Result.success()
        } catch (retryable: IOException) {
            Result.retry()
        } catch (fatal: IllegalArgumentException) {
            Result.failure()
        }
    }
}

Device Reality

WorkManager is Doze-aware and persistent, not instant. OEM battery managers can delay work more aggressively than a Pixel emulator. Test important jobs on the device class users actually own.