This thesis aims to solve the degrading state of the web application of the Online Seminar of Informatics (KSI). The current web application is built upon an unsupported web framework, which cannot be easily updated to its supported version. To resolve this issue, this thesis creates a new implementation of the said web application, which will use a technology that is expected to be maintainable in the long term. First, it discusses which technology is best suited for a given use case and then presents the solution, together with changes made to the KSI backend and a new KSI frontend. As a result, the new web application is shown with two active deployments. One of which is used as a production environment for a new online seminar, which is possible due to the high focus on easy modularity throughout the development process.