A natural language specification of at least one high level information technology services requirement is obtained from a user, via a conversational interface; the same is parsed into first pre-defined semi-structured data, using a conversation parser. Based on the first pre-defined semi-structured data, a subset of candidate information technology services is identified, with a dialog engine, from a plurality of candidate information technology services provided by a plurality of vendors, the dialog engine is used to formulate a response including second pre-defined semi-structured data. The response is reverse-parsed into a natural language response, using the conversation parser. The natural language response includes a question for the user to assist in further refining the subset of candidate information technology services; the natural language response is presented to the user via the conversational interface.