diff --git a/main.go b/main.go
index 05a29f4..8337251 100644
--- a/main.go
+++ b/main.go
@@ -30,7 +30,7 @@ type SlackConfig struct {
 
 // PostHandler send notifications from synology to slack
 func PostHandler(w http.ResponseWriter, r *http.Request) {
-        api = r.Header.Get("api_key")
+        api := r.Header.Get("api_key")
 	if r.Header.Get("api_key") != appConfig.APIKey {
 		http.Error(w, "invalid api key", http.StatusUnauthorized)
 		log.Printf("invalid api key: %s", api)