diff --git a/controller.go b/controller.go
index 11484a4..92162eb 100644
--- a/controller.go
+++ b/controller.go
@@ -63,6 +63,7 @@ func (h *Handler) getRsvps(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	w.Header().Add("Content-Type", "application/json")
 	w.WriteHeader(http.StatusOK)
 	fmt.Fprintf(w, "%s", marshalledRsvps)
 }