Paramatrix Application Core Engine (PACE) is a rapid application development framework, which allows the software developers to concentrate more on business logic of the application, rather than on peripheral sub-systems needed to run it. It is useful as the backbone (middleware) of enterprise applications. It consists of many loosely coupled components, which are responsible for carrying out various operations. It takes care of providing support to major peripheral supporting systems and functionalities required for middleware-oriented applications. With the PACE-based approach to application development, the software developer is only entrusted with the task of writing code to fulfill the business-related needs of the application. It is done by creating custom classes in either Java or C#, and then implementing various methods in it. Once these classes and their methods are registered with the PACE engine, it will be readily available for client applications. All general plumbing work required for building a non-trivial application is taken care of by this framework.