A common goal among experienced web developers is to develop and deploy applications that are flexible and easily maintainable. An important consideration in reaching this goal is the separation of business logic from presentation logic.^[1] Developers use web template systems (with varying degrees of success) to maintain this separation.^[1]

One difficulty in evaluating this separation is the lack of well-defined formalisms to measure when and how well it is actually met.^[1] There are, however, fairly standard heuristics that have been borrowed from the domain of software engineering. These include 'inheritance' (based on principles of object-oriented programming); and the 'Templating and Generative programming', (consistent with the principles of MVC separation).^[2] The precise difference between the various guidelines is subject to some debate, and some aspects of the different guidelines share a degree of similarity.^[3]