diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/orientation/DeviceOrientation.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/orientation/DeviceOrientation.kt
index 9c4e753406..f24fbe9d19 100644
--- a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/orientation/DeviceOrientation.kt
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/orientation/DeviceOrientation.kt
@@ -7,7 +7,7 @@ external interface DeviceOrientation {
     val beta: Double
     val gamma: Double
 
-    fun start(params: DeviceOrientationStartParams, callback: (Boolean) -> Unit)
+    fun start(params: DeviceOrientationStartParams, callback: (Boolean) -> Unit = definedExternally)
     fun stop(callback: (Boolean) -> Unit)
 }