diff --git a/app/serializers/auth_provider_serializer.rb b/app/serializers/auth_provider_serializer.rb
index d7bc83afc29..ae8a54e48d8 100644
--- a/app/serializers/auth_provider_serializer.rb
+++ b/app/serializers/auth_provider_serializer.rb
@@ -20,4 +20,9 @@ class AuthProviderSerializer < ApplicationSerializer
     return SiteSetting.get(object.pretty_name_setting) if object.pretty_name_setting
     object.pretty_name
   end
+
+  def custom_url
+    # ensures that the "/custom" route doesn't trigger the magic custom_url helper in ActionDispatch
+    object.custom_url
+  end
 end
diff --git a/config/routes.rb b/config/routes.rb
index 937d9b4e152..cfaec12f630 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1615,6 +1615,8 @@ Discourse::Application.routes.draw do
          constraints: HomePageConstraint.new("custom"),
          as: "custom_index"
 
+    get "/custom" => "custom_homepage#index"
+
     get "/user-api-key/new" => "user_api_keys#new"
     post "/user-api-key" => "user_api_keys#create"
     post "/user-api-key/revoke" => "user_api_keys#revoke"