diff --git a/SVSimLoader/Patches/UrlPatches.cs b/SVSimLoader/Patches/UrlPatches.cs
index f617af5..511c6b0 100644
--- a/SVSimLoader/Patches/UrlPatches.cs
+++ b/SVSimLoader/Patches/UrlPatches.cs
@@ -14,4 +14,20 @@ public static class UrlPatches
         __result = SvSimConfig.ApplicationUrl;
         return false;
     }
+
+    /// <summary>
+    /// Redirects the deck-builder server (shadowverse-portal.com in prod) to our app server so
+    /// the deck-code mint/resolve pair lands on the emulator's <c>DeckBuilderController</c>.
+    /// Both client tasks (<c>GenerateDeckCodeTask</c>, <c>GetDeckDataFromCodeTask</c>) build
+    /// their URL as <c>GetDeckBuilderServerURL() + ApiList[type]</c> where the right-hand side
+    /// is the bare <c>deck_code?format=msgpack</c> / <c>deck?format=msgpack</c> path — matches
+    /// our controller routes once this prefix returns the local server's base URL.
+    /// </summary>
+    [HarmonyPatch(typeof(CustomPreference), nameof(CustomPreference.GetDeckBuilderServerURL))]
+    [HarmonyPrefix]
+    public static bool GetDeckBuilderServerURL(ref string __result)
+    {
+        __result = SvSimConfig.ApplicationUrl;
+        return false;
+    }
 }
\ No newline at end of file