Abstract: Embodiments of the invention provide systems and methods for defining and executing custom business rules to influence or control execution of a business process and allowing software providers to deliver externally extensible business applications which in turn allow customers of those applications to implement their own business rules and conditions using a browser based UI, without modifying the actual code in the base application. A user interface (UI) based business rule configurator allows users to define business rules and conditions that can be executed by a rules engine integrated with the client extensions and no custom code is required for business users to extend the business logic and no future custom code maintenance is required.