E-commerce is one of the most important web applications. We present here a set of patterns that describe shopping carts, products, catalogue, customer accounts, shipping, and invoices. We combine them in the form of composite patterns, which in turn make up a domain model for business-to-consumer e-commerce. We also indicate how to add security constraints to this model. This domain model can be used as a computation-independent model from which specific applications can be produced using a model-driven architecture approach.