1. A method of executing a sequence of a plurality of application programming interfaces comprising: generating request objects for the application programming interfaces of the sequence, wherein each request object is generated in accordance with a common object model, wherein each of a collection of application programming interfaces is associated with a key and a definition for the sequence includes a list of keys of application programming interfaces from the collection included in the sequence, and wherein an order of the keys in the definition specifies an order of execution of the associated application programming interfaces; and enabling execution of each application programming interface in an order of the sequence to process a corresponding request object and generate a corresponding response object containing results, wherein each response object is generated in accordance with the common object model and includes information from the corresponding request object aggregated with the results, and wherein each request object for a succeeding application programming interface in the sequence includes the aggregated information from a response object of a prior executed application programming interface in the sequence, and wherein enabling execution further comprises: identifying one or more objects in a request object unrecognized by a corresponding application programming interface: and placing the one or more unrecognized objects in a separate storage area of the request object and corresponding generated response object for processing by at least one succeeding application programming application interface in the sequence recognizing the one or more unrecognized objects, wherein the separate storage area is reserved for unrecognized objects.