diff --git a/source/mijin/net/http.hpp b/source/mijin/net/http.hpp
index 89f2390..ebcbf91 100644
--- a/source/mijin/net/http.hpp
+++ b/source/mijin/net/http.hpp
@@ -18,11 +18,11 @@ namespace mijin
 {
 namespace http_method
 {
-inline constexpr std::string GET = "GET";
-inline constexpr std::string POST = "POST";
-inline constexpr std::string HEAD = "HEAD";
-inline constexpr std::string PUT = "PUT";
-inline constexpr std::string DELETE = "DELETE";
+inline const std::string GET = "GET";
+inline const std::string POST = "POST";
+inline const std::string HEAD = "HEAD";
+inline const std::string PUT = "PUT";
+inline const std::string DELETE = "DELETE";
 }
 
 struct HTTPVersion