The development phase is an extension of the prototype development phase. In this phase the concrete system Architecture is implemented using a selected software tool or language. The business logic is created and integrated with the commerce engine. I.e. the core of the electronic commerce portal is developed. The GUI (Graphical User Interface) is also developed based on the storybook and the requirements document. Besides functionality the content is also a significant element. The content comprises all the information that the electronic commerce portal provides, as well as its presentation within the user interface. Content often has multi-media characteristics, i.e. it comprises textual information, graphic figures, moving and still pictures and audio information.

The development procedures are well documented and also the user manuals are created. User manuals can be differentiated into tutorials and references. For the creation of the user manuals, a style guide is used that describes what the complete user documentation will look like.