Formal modeling of RESTful systems using finite-state machines

Abstract. Representational State Transfer (REST), as an architectural style for distributed hypermedia systems, enables scalable operation of the World Wide Web (WWW) and is the foundation for its future evolu-tion. However, although described over 10 years ago, no comprehensive formal model for representing RESTful systems exists. The lack of a for-mal model has hindered understanding of the REST architectural style and the WWW architecture, consequently limiting Web engineering ad-vancement. In this paper we present a model of RESTful systems based on a finite-state machine formalism. We show that the model enables in-tuitive formalization of many REST’s constraints, including uniform in-terface, stateless client-server operation, and code-on-demand execution. We describe the model’s mapping to a system-level view of operation and apply the model to an example Web application. Finally, we outline benefits of the model, ranging from better understanding of REST to designing frameworks for RESTful system development