Abstract: A multi-merchant portal that enables a user to access e-commerce stores is provided. Each e-commerce store has respective merchant categories browsable by the user at a customer device through the portal, each merchant category comprising products available for purchase from a respective merchant. In response to receiving a request from the customer device to switch access of the user browsing a selected merchant category of the first merchant in a first e-commerce store, to a second e-commerce store, the portal determines a system category corresponding to the selected merchant category using mapping data mapping merchant categories to system categories and then determines a destination merchant category of the second merchant in the second e-commerce store corresponding to the determined system category using mapping data mapping the system categories to the merchant categories. The portal switches user's access to the destination merchant category in the second e-commerce store.

Abstract: A multi-merchant portal that enables a user to access e-commerce stores is provided. Each e-commerce store has respective merchant categories browsable by the user at a customer device through the portal, each merchant category comprising products available for purchase from a respective merchant. In response to receiving a request from the customer device to switch access of the user browsing a selected merchant category of the first merchant in a first e-commerce store, to a second e-commerce store, the portal determines a system category corresponding to the selected merchant category using mapping data mapping merchant categories to system categories and then determines a destination merchant category of the second merchant in the second e-commerce store corresponding to the determined system category using mapping data mapping the system categories to the merchant categories. The portal switches user's access to the destination merchant category in the second e-commerce store.

Abstract: A server for processing transactions within a Representational State Transfer (REST) architecture is provided. The server includes an input for receiving requests from a client device and a processor arranged to store received requests in a data store. In response to receiving a request to commit the transaction, the processor is arranged to retrieve stored requests from the data store and sequentially process the retrieved requests. The server also includes an output that is arranged to output a transaction result to the client device.