> This page is part of the [Customer.io documentation](https://docs.customer.io). For the complete index, see [llms.txt](https://docs.customer.io/llms.txt).
> Last updated: November 13, 2026
> To take actions in Customer.io from an agent, use the [Customer.io CLI](https://docs.customer.io/ai/cli/get-started.md) or the [MCP server](https://docs.customer.io/ai/mcp/get-started.md).

# Silent push

A silent push wakes your app in the background and hands it the data set on the message, without showing anything to the person. Use this page to set your app up to receive silent pushes.

## How it works

When you send a [silent push](https://docs.customer.io/messaging/channels/push/silent-push/), Firebase delivers a data-only message to your app, even when your app is in the background. The SDK reports *Delivered* to Customer.io and passes the key/value data set on the message to a callback you register. The SDK doesn’t show a notification or open a link for a silent push, and it doesn’t report *Opened*.

Silent push needs version 5.1.0 or later of the Android SDK. Older versions ignore silent pushes. Customer.io sends silent pushes to every Android device a message targets, and doesn’t check which SDK version the device uses.

## Set up silent push

Register a callback with `setBackgroundPushCallback` when you configure the push module in `Application.onCreate`, where you initialize the SDK. Firebase can start your app’s process in the background only to deliver a silent push, and only a callback that you register during startup receives it.

```
val builder = CustomerIOConfigBuilder(
    applicationContext = this,
    cdpApiKey = "your-cdp-api-key"
).addCustomerIOModule(
    ModuleMessagingPushFCM(
        MessagingPushModuleConfig.Builder()
            .setBackgroundPushCallback { context, payload ->
                // Key your work on payload.deliveryId: the same push can arrive more than once.
                enqueueAccountRefresh(context, payload.deliveryId, payload.data)
            }
            .build()
    )
)

CustomerIO.initialize(builder.build())
```

The callback gets a `CustomerIOBackgroundPushPayload`:

Property

Description

`deliveryId`

Identifies the delivery. A repeat of the same push has the same ID.

`data`

The keys and values set on the message, without Customer.io’s delivery keys or Firebase’s metadata.

`deliveryToken`

The device token the push was sent to. You only need it to [track *Delivered* yourself](https://docs.customer.io/integrations/sdk/android/push/push/#capture-push-metrics) when you turn off automatic push tracking.

The SDK calls your callback on the thread that handed it the message, and Firebase gives that thread only a short time. Keep the callback short, and hand longer work to WorkManager.

If your app has its own `FirebaseMessagingService` that forwards messages to `CustomerIOFirebaseMessagingService.onMessageReceived`, as described in [push notifications](https://docs.customer.io/integrations/sdk/android/push/push/), silent pushes reach your callback the same way. `onMessageReceived` returns `true` for a silent push.

When automatic push tracking (`autoTrackPushEvents`) is on, which is the default, the SDK reports *Delivered* for each silent push. If you don’t register a callback, the SDK still reports *Delivered* and drops the data.

## What to plan for

Firebase and Android decide when to deliver a silent push, and don’t always deliver it:

*   **Repeats**: The same push can arrive more than once, and the SDK calls your callback for every copy it receives. Use `deliveryId` to skip work you already did.
*   **Delays**: Android can hold normal-priority messages while the device is idle. If your app needs the data right away, set the message’s **Android priority** to **High** in Design Studio. Firebase may still lower the priority of high-priority messages that keep showing no notification.
*   **Offline devices**: After a device has been offline, silent pushes can arrive late, out of order, or not at all. Treat each silent push as a signal to fetch the latest state from your own backend.
*   **Force-stopped apps**: Android doesn’t deliver pushes to an app the person force-stopped.