[android-components](../../index.md) / [mozilla.components.concept.engine.webpush](../index.md) / [WebPushSubscription](index.md) / [appServerKey](./app-server-key.md)

# appServerKey

`val appServerKey: `[`ByteArray`](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)`?` [(source)](https://github.com/mozilla-mobile/android-components/blob/master/components/concept/engine/src/main/java/mozilla/components/concept/engine/webpush/WebPush.kt#L53)

A public key a server will use to send messages to client apps via a push server.

