In schul-frei we do not offer a solution that can fit all problems.
We choose several solutions which are responsible for their own tasks. Each of them supports a good integration into the other tools, so it seems to be one solution.
The DebianEdu operating system is suitable as a free school network solution for desktops or servers. It is specially developed for use in schools: software packages for school administration and teaching are integrated. It is also ideal for the use of other open source solutions. With DebianEdu you can build a stable working network that is immediately suitable for workstations.
AlekSIS is a web-based information management system for schools and other educational institutions. It supports internal organization, also information can be published through it. It also offers many apps that cover a large part of all school needs. However, if any functionality is missing, AlekSIS offers the possibility to write an app yourself. AlekSIS is designed to be easy to use and customizable. It is developed by Teckids e.V. and students of Katharineum zu Lübeck.
Moodle is a self-hosted learning management system that makes it possible to deliver course content and assignments to classes or courses online. This platform makes it possible to create course rooms in which students are assigned by teachers in order to provide them with content from class or a study group digitally. Learning outcomes can be monitored by teachers using Moodle, as assignments can be set and results assessed and feedback provided.
Jitsi is a video conferencing system that allow schools to make online lessons.
Especially during the pandemic it has become frequently used.
Nextcloud is a free cloud service that can be self-hosted and used in school operations. It is suitable for sharing files with groups, such as classes or courses. These files can also be edited together in real time, which can simplify group work, for example. In addition to the classic cloud functions, a shared calendar and a survey function are also available.