Model Solution of GraphQL Client-Server Application

This ‘Diploma Thesis’ has been developed and is focused on GraphQL Technology, specifically its application on the client-server model solution.The first section of the thesis pursues the theoretical aspects of communication between two connected devices by an internet network. Additionally, it will concern the traditional approach of REST API and its comparison with the GraphQL concept, especially in regard to server sides and client sides. Furthermore, the thesis assesses the principles and methodology of developing REST API/GraphQL, analyzing the advantages and disadvantages in comparison to the traditional approach of REST API. In particular, focus will be on: design patterns; type system; SDL language; methods of introspection; code validation; creation of questions and mutations; and modifying data in database.The practical section of the thesis focuses on the actual use of this technology. The overall goal is to create a model solution of a web application, one which communicates between server and client via using GraphQL technology. Before the application of this practical methodology, in the introduction of this section, a description of the implementation tools, used by the above web application solution, will be offered. Furthermore, the individual parts of the application are described in an order that reflects the process of its development up-until the first running of the app.The final section of the thesis offers a summary of results, in addition to addressing whether the aims of the study – presented in earlier sections of the work – were met. Following this, a suggestion for the possible development of this research will be discussed.