The built form of a city is a legacy of past property development, yet the processes that lead to particular developments in time and space are complex and the stakeholders numerous. The paper briefly reviews major themes in the literature and argues that a multi-disciplinary approach can add to knowledge of how development systems work. Model builders have often used diagrams to illustrate their concepts though as detail inevitably increases these lose focus. A previous paper called for new software, designed to help untangle the relationships and heterogeneity of the development process. As a step along that road, a model has been built on a web platform using hyperlinks to trace the interactions. The paper describes how the website tracks the complex and overlapping sets of relationships that typically exist between elements of the process such as markets, institutions and events. The model consists of 7 defined major elements and 51 defined subsidiary elements. The latter are functionally inter-linked by a dense web of described input-output relationships. The operation of the web-model is examined in using three recent case studies located in the Grainger Town area of Newcastle upon Tyne, UK. It is argued that the web-model presented has potential to integrate disparate forces leading to property development and that further refinement is justified.