diff --git a/main.go b/main.go
index 3efbf5f..d028c5d 100644
--- a/main.go
+++ b/main.go
@@ -28,10 +28,10 @@ func main() {
 
 	router.HandleFunc("/", h.RequestHandler).Methods("GET")
 	router.HandleFunc("/healthcheck", h.HealthHandler)
-	router.HandleFunc("/OS", h.GetOS).Methods("GET")
-	router.HandleFunc("/OS/{id}", h.GetOSbyID).Methods("GET")
+	router.HandleFunc("/os", h.GetOS).Methods("GET")
+	router.HandleFunc("/os/{id:[0-9]+}", h.GetOSbyID).Methods("GET")
 	router.HandleFunc("/distribution", h.GetDistributionList).Methods("GET")
-	router.HandleFunc("/distribution/{distribution}/version", h.GetVersionByDistributionList).Methods("GET")
+	router.HandleFunc("/distribution/{distribution:[a-zA-Z]+}/version", h.GetVersionByDistributionList).Methods("GET")
 
 	log.Fatal(http.ListenAndServe(":8080", router))
 }