Why are my time-sensitive scheduled notifications being delayed, and how can I improve delivery precision?

When you schedule a push notification, Pushwoosh hands it to the platform gateway (FCM for Android, APNs for iOS) at the scheduled time. Final delivery to the device is then up to the gateway and the device operating system, where delays can occur.

Android devices

The most common cause of Android delays is aggressive battery optimisation, especially on devices from Xiaomi, Huawei, Samsung and similar manufacturers.

• Doze mode: when a device is idle, Android defers network access and background work to periodic maintenance windows, which delays delivery.
• Manufacturer customisations: many vendors add battery-saving systems stricter than stock Android, sometimes killing background app processes outright.

What you can change in the payload

• android_delivery_priority — set to "high" to have the notification delivered even when the device is in power-saving mode. This is the single most effective server-side setting for time-sensitive Android pushes.
• android_priority — values -2 to 2. Sets the notification channel importance on Android 8.0+ (and the priority on Android 7.1 and lower), which controls how intrusively the notification is surfaced.

What you can change on the device

Check the battery and power-saving settings on your test devices and make sure your application is whitelisted or exempted from battery optimisation so it can receive notifications in real time.

iOS devices

Pushwoosh already configures the key APNs headers for immediate delivery of standard, user-facing notifications:

• apns-priority is set to 10 (highest), telling APNs to deliver immediately.
• apns-push-type is set to alert, the correct type for notifications that show an alert, play a sound, or badge the icon.

Critical and time-sensitive alerts (iOS 15+)

Use the ios_interruption_level parameter in your /createMessage request to let a notification break through Focus modes and the Scheduled Summary. Accepted values are passive, active (default), time-sensitive and critical. time-sensitive requires the Time Sensitive Notifications entitlement, and critical requires Apple's Critical Alerts entitlement.