Context: establishing forms of unified communication in Aknowledge Systems of Systems (SoS) is a difficult and complex task that requires constant studies by the developer on current versions of APIs of other constituent systems, connection forms, data request and return. Objective: in order to minimize that aspect, this paper proposes a new approach, called MicroGraphQL, to allow fast and unified communication of constituent systems through GraphQL. To this end, the approach uses 2 microservices (API Similarity Analyzer Service, GraphQL Code Generator Service) and a GraphQL Gateway, which together analyze communication similarities between APIs and generate GraphQL code for these similarities. Methods: the proof-of-concept of the approach is supported by the microGraphQLTool tool, which implements the microservices and the GraphQL Gateway using the JavaScript language and the Apollo library. Results: the applicability of the proposed approach is successfully performed in two real APIs of systems constituting a sales SoS of a multinational company, allowing the use of GraphQL to unify them. Conclusion: the approach supports the development of new forms of SoS integration, facilitating developers’ activities in relation to obtaining information from APIs of other systems.