diff --git a/event/event.go b/event/event.go
index 2cc4d1f..85a0d03 100644
--- a/event/event.go
+++ b/event/event.go
@@ -72,9 +72,10 @@ const (
 	TrackCart        Type = "track.cart"       // 3,4 — add to / remove from cart
 	TrackImpression  Type = "track.impression" // 5 — impression
 	TrackAction      Type = "track.action"     // 6 — custom action (wishlist, etc.)
-	TrackPageView    Type = "track.page_view"
-	TrackPageEngaged Type = "track.page_engaged"
-	TrackPageAction  Type = "track.page_action"
+	TrackPageView       Type = "track.page_view"
+	TrackPageEngaged    Type = "track.page_engaged"
+	TrackPageAction     Type = "track.page_action"
+	TrackExperiment     Type = "track.experiment"
 )
 
 // Event is the one envelope. Payload is per-Type, agreed between producer and