diff --git a/src/Ryujinx.Horizon/Sdk/Am/AppletMessage.cs b/src/Ryujinx.Horizon/Sdk/Am/AppletMessage.cs
new file mode 100644
index 000000000..7d88b72fa
--- /dev/null
+++ b/src/Ryujinx.Horizon/Sdk/Am/AppletMessage.cs
@@ -0,0 +1,39 @@
+namespace Ryujinx.Horizon.Sdk.Am
+{
+    public enum AppletMessage : byte
+    {
+        None = 0,
+        ChangeIntoForeground = 1,
+        ChangeIntoBackground = 2,
+        Exit = 4,
+        ApplicationExited = 6,
+        FocusStateChanged = 15,
+        Resume = 16,
+        DetectShortPressingHomeButton = 20,
+        DetectLongPressingHomeButton = 21,
+        DetectShortPressingPowerButton = 22,
+        DetectMiddlePressingPowerButton = 23,
+        DetectLongPressingPowerButton = 24,
+        RequestToPrepareSleep = 25,
+        FinishedSleepSequence = 26,
+        SleepRequiredByHighTemperature = 27,
+        SleepRequiredByLowBattery = 28,
+        AutoPowerDown = 29,
+        OperationModeChanged  = 30,
+        PerformanceModeChanged = 31,
+        DetectReceivingCecSystemStandby = 32,
+        SdCardRemoved = 33,
+        LaunchApplicationRequested = 50,
+        RequestToDisplay = 51,
+        ShowApplicationLogo = 55,
+        HideApplicationLogo = 56,
+        ForceHideApplicationLogo = 57,
+        FloatingApplicationDetected = 60,
+        PerformanceConfigurationChanged = 61,
+        DetectShortPressingCaptureButton = 90,
+        AlbumScreenShotTaken = 92,
+        AlbumRecordingSaved = 93,
+        DetectShortPressingCaptureButtonForApplet = 110,
+        DetectLongPressingCaptureButtonForApplet = 111
+    }
+}