diff --git a/webpack.config.js b/webpack.config.js
index 1a2e183e..f073a689 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -71,7 +71,7 @@ var config = {
             'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV),
             'APP_BAR_TITLE': JSON.stringify(process.env.APP_BAR_TITLE || "Optuna Dashboard"),
             'API_ENDPOINT': JSON.stringify(process.env.API_ENDPOINT),
-            'URL_PREFIX': JSON.stringify(process.env.API_ENDPOINT || "/dashboard")
+            'URL_PREFIX': JSON.stringify(process.env.URL_PREFIX || "/dashboard")
         })
     ],
     externals