It has to be determined if the selected software systems provided a programming interface (API) or if an interface could be developed. This would be achieved by developing prototypes on the basis of the use cases and requirements, with the goal to identify opportunities for integrating the software systems with each other. For each software system, key features would be defined that had to be realized by the prototype. The prototypes should show if the features of the underlying software system could be accessed through its interface.
Based on the prototypes, the effort, cost and time for the development of the whole eCommerce portal system could be estimated. This estimate was used to verify the "time-to-market" that was aimed for in the business plan. The prototype development would also help in identifying the resources required, complexity in data integration etc. For Internet start-ups the prototype would solve as a working model of the idea and could be shown to their potential investors to seek early stage funding.