In recent years, agile methodologies have been consolidated and extended in organizations that develop software in Web environments. For this reason, the development methodology of these organizations will not only be related to Services, but also to the Web Engineering paradigm. These organizations are heading for incorporating software development methodologies whose paradigm can allow integration, naturally and in the earlier stages of Web applications develop with the services of the organization that described and published in the Services Portfolio. The aim of this study will be to analyze the current state of the art in the process of discovering services in early stages of agile software development with focus on those identified requirements that could be covered with the services included in the Service Portfolio. We have identified 20 relevant papers through conducting a double systematic literature review (SLR). It is concluded that no study has been found that can solve the entire process of discovering candidate services within an organization that cover the requirements of a new application developed with agile methodologies. At the same time, guidelines have been found to formalize the solution to this problem and fill in that gap of knowledge by proposing in a single process, the formalization of a requirement based on agile techniques, which can be managed against a Services Portfolio.