A generic application program interface (API) may learn heterogeneous APIs based on their API documentations that understands functionalities, parameters, operations, accessibility and outputs of APIs. The generic API collects API documentation from different sources based on a target human language by crawling a network such as the Internet. The generic API reads the documents of an API to recognize features of an API including type of services, concepts, protocols, accessibility methods, security methods, functionalities, outputs and base operations. Each given instruction for different APIs is mapped to generic API features. A programmer or end-user have access to multiple and heterogeneous APIs based on the generic API. The generic API provides a unified interface that allows a programmer or end-user to interact with different target APIs through the generic API. By raising a request to generic API a native API code is generated, executed and returns to the programmer or end-user.