diff --git a/backend/cmd/db/main.go b/backend/cmd/db/main.go
index d3d786242..20d6ce55b 100644
--- a/backend/cmd/db/main.go
+++ b/backend/cmd/db/main.go
@@ -31,9 +31,9 @@ func main() {
 	defer pg.Close()
 
 	// HandlersFabric returns the list of message handlers we want to be applied to each incoming message.
-	handlersFabric := func() {
+	handlersFabric := func() []handlers.MessageProcessor {
 		return []handlers.MessageProcessor{
-			custom.EventMapper{},
+			&custom.EventMapper{},
 			custom.NewInputEventBuilder(),
 			custom.NewPageEventBuilder(),
 		}
diff --git a/backend/cmd/heuristics/main.go b/backend/cmd/heuristics/main.go
index 6712c927c..6edf01a92 100644
--- a/backend/cmd/heuristics/main.go
+++ b/backend/cmd/heuristics/main.go
@@ -26,7 +26,7 @@ func main() {
 	cfg := ender.New()
 
 	// HandlersFabric returns the list of message handlers we want to be applied to each incoming message.
-	handlersFabric := func() {
+	handlersFabric := func() []handlers.MessageProcessor {
 		return []handlers.MessageProcessor{
 			// web handlers
 			&web.ClickRageDetector{},