The graduation thesis describes the development of a web application for the maintenance of the distribution system, which was re-developed with the help of newer technologies and the transfer of the functionality of the old web application based on the existing data model. The old web application was developed with the help of technologies which are already outdated, due to lack of maintenance, there were some weaknesses in the functionalities, some even stopped working, which made the parts in the subscriber's company more difficult. Using the old web application, the work was also carried out manually by filling out forms in paper form. In the newly developed web application, we also added functionality based on the work process, with this functionalitis we displaced manual work and thus facilitated the work of employees. All the technologies and tools that have been used during the development are described. We also describe the data model on the basis of which we developed the web application and all the functionality contained. The following is a description of the operation of the web application, based on which we tested and evaluated the testing of user interfaces of the old and new web applications, and the conclusions reached during the development process.