diff --git a/NineChronicles.Headless/GraphQLServiceExtensions.cs b/NineChronicles.Headless/GraphQLServiceExtensions.cs
index 9820b3d93..07dc8b680 100644
--- a/NineChronicles.Headless/GraphQLServiceExtensions.cs
+++ b/NineChronicles.Headless/GraphQLServiceExtensions.cs
@@ -48,6 +48,7 @@ public static IServiceCollection AddLibplanetScalarTypes(this IServiceCollection
             services.TryAddSingleton<Libplanet.Explorer.GraphTypes.VoteType>();
             services.TryAddSingleton<Libplanet.Explorer.GraphTypes.BlockCommitType>();
             services.TryAddSingleton<Libplanet.Explorer.GraphTypes.BoundPeerType>();
+            services.TryAddSingleton<Libplanet.Explorer.GraphTypes.DiffValueType>();
 
             return services;
         }