Web Services Composition can be defined as bringing together a number of web services in a certain workflow to achieve a certain task that cannot be achieved by any of the composed services alone. In general, it involves first the discovery of the suitable services over the Web, and compose them in a certain workflow order and finally run the composed service which is the invocation stage. WSC has been a highly active research topic since the emergence of Web services in 2000s. "Manual" WSC is the form that the activities of discovery, composition and invocation are all done manually (by human). In the "Semi-automated" way, the discovery is done by the machine. In the "full-automated" approach all the above activities are done by the machine. There are no tools at the moment that achieve full automated composition. Web API composition is like WSC, the only difference is the fact that instead of web services there are Web APIs in WAPIC. There is no doubt that One would run into the very same problems of WSC concerning full automated composition. In other words, WAPIC would in no way be easier than WSC. Nevertheless, as far as semi automated form can be achived, WAPIC is valuable because the number of Web APIs increase drastically from day to day. The site "programmableWeb" lists 14 957 APIs at the moment. It is not easy to search for all those APIs manually for the discovery of suitable APIs for a given task.