diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/EventHandler.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/EventHandler.kt
index f56acf10d2..4d4e82a125 100644
--- a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/EventHandler.kt
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/EventHandler.kt
@@ -1,4 +1,4 @@
 package dev.inmo.tgbotapi.webapps
 
 typealias EventHandler = WebApp.() -> Unit
-typealias ViewportChangedEventHandler = WebApp.(Boolean) -> Unit
+typealias ViewportChangedEventHandler = WebApp.(ViewportChangedData) -> Unit
diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/ViewportChangedData.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/ViewportChangedData.kt
new file mode 100644
index 0000000000..6f4dd3054a
--- /dev/null
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/ViewportChangedData.kt
@@ -0,0 +1,5 @@
+package dev.inmo.tgbotapi.webapps
+
+external interface ViewportChangedData {
+    val isStateStable: Boolean
+}
diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebApp.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebApp.kt
index fbba60f883..5422c340c2 100644
--- a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebApp.kt
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebApp.kt
@@ -19,11 +19,11 @@ external class WebApp {
 
     internal fun onEvent(type: String, callback: () -> Unit)
     @JsName("onEvent")
-    internal fun onEventWithBoolean(type: String, callback: (Boolean) -> Unit)
+    internal fun onEventWithBoolean(type: String, callback: (ViewportChangedData) -> Unit)
 
     fun offEvent(type: String, callback: () -> Unit)
     @JsName("offEvent")
-    fun offEventWithBoolean(type: String, callback: (Boolean) -> Unit)
+    fun offEventWithBoolean(type: String, callback: (ViewportChangedData) -> Unit)
 
     fun sendData(data: String)
 
@@ -54,7 +54,7 @@ fun WebApp.onEvent(type: EventType, eventHandler: EventHandler) = {
 /**
  * @return The callback which should be used in case you want to turn off events handling
  */
-fun WebApp.onEvent(type: EventType.ViewportChanged, eventHandler: ViewportChangedEventHandler) = { it: Boolean ->
+fun WebApp.onEvent(type: EventType.ViewportChanged, eventHandler: ViewportChangedEventHandler) = { it: ViewportChangedData ->
     eventHandler(js("this").unsafeCast<WebApp>(), it)
 }.also {
     onEventWithBoolean(