diff --git a/response.go b/response.go
index f0c6970..f2a19c1 100644
--- a/response.go
+++ b/response.go
@@ -59,6 +59,10 @@ const (
 	HorizontalImageAspectRatio ImageAspectRatio = "horizontal"
 	// ImageAspectRatio is square.
 	SquareImageAspectRatio ImageAspectRatio = "square"
+
+	SenderActionMarkSeen  SenderAction = "mark_seen"
+	SenderActionTypingOn  SenderAction = "typing_on"
+	SenderActionTypingOff SenderAction = "typing_off"
 )
 
 // QueryResponse is the response sent back by Facebook when setting up things