diff --git a/api/middleware.go b/api/middleware.go
index e761f50..bfa2c75 100644
--- a/api/middleware.go
+++ b/api/middleware.go
@@ -18,7 +18,7 @@ const (
 func authMiddleware(tokenMaker token.Maker) gin.HandlerFunc {
 	return func(ctx *gin.Context) {
 		authHeader := ctx.GetHeader(authHeaderKey)
-		if len(authHeader) == 0 {
+		if authHeader == "" {
 			err := errors.New("authorization header is not provided")
 			ctx.AbortWithStatusJSON(http.StatusUnauthorized, errorResponse(err))
 			return