Cornelsen Verlag GmbH is one of the leading educational publishers in Germany and a key player in the country’s education landscape.

With decades of experience in creating high-quality learning materials, Cornelsen supports schools, teachers and students through a wide range of digital and print solutions.

Their learning platform, Cornelsen Lernen, brings education into the digital age. It enables schools and institutions to manage lessons, assignments and multimedia resources in one place, making learning more interactive and accessible.

By combining proven teaching methods with innovative technology, Cornelsen continues to shape the future of digital education across Germany.

Cornelsen already had web and mobile applications in place, serving administrators, teachers and students. Their primary goal was to allow schools to manage lessons, assignments and learning materials, while tracking student progress.

The client’s goal was to keep these applications stable, secure and running smoothly, while delivering new features along a predefined two-year roadmap. That is exactly where we stepped in, to modernise the technical foundations where needed and improve performance, all without disrupting day-to-day use.

The project focused on two main goals, keeping Cornelsen’s applications stable and high-performing, and modernising them to support future growth.

The web application

The web platform initially existed as three separate applications for administrators, teachers and students. This structure caused duplicated code, slowed development and made deployments more complex. We merged them into a single monorepository, which simplified maintenance and sped up feature delivery.

Alongside the merge, we refactored the codebase and updated dependencies. These improvements enhanced performance and reliability, while the gradual introduction of GraphQL alongside REST APIs allowed the system to handle data more efficiently.

The back end was upgraded from Java 17 to Java 21 and Redis 6 to Redis 7. On the front end, unit and integration tests were added for every new feature to maintain high quality and prevent regressions.

The mobile application

We collaborated to modernise the mobile app and introduce new features that enhanced usability and addressed real user needs. Here are some of the most exciting features that we added to the mobile app:

• the guest user mode that allows students and teachers to explore content without a licence, making it easier to try out materials and increasing engagement with the platform;
• the barcode scanner was added to streamline the process of finding books. Instead of manually searching titles, teachers and students could quickly scan a book’s barcode and access its digital resources, saving time and improving workflow efficiency;
• lesson planning tools were developed to support teachers in organising tasks and assignments. With these tools, teachers could create, assign and track lessons directly within the app, giving them a clearer overview of student progress and reducing administrative workload.

Additionally, we refactored the legacy code to reduce technical debt and prepare the apps for future updates. The adoption of Kotlin and Jetpack Compose is planned, ensuring scalability, maintainability and long-term stability.

The platforms now run more reliably, handling daily use with improved performance and fewer errors. The mobile features that we have implemented together now have streamlined workflows, making the apps more intuitive and useful for teachers and students.

Most importantly, user adoption and engagement continue to grow, with approximately 20,000 iOS users and 2,000 Android users. Rising app ratings reflect improved satisfaction and confidence in the platform.