This thesis deals with the analysis and extension of the DEMoS web application designed for transcribing genealogical sources. The aim of the thesis is to design and implement mechanisms that prevent loss of higher-trust contributions when multiple users edit the same record, and at the same time enable effective collaboration between users with different levels of permissions. Building on the existing user-level system, the thesis introduces
fine-grained permissions for individual record items and stores,
for each edit, the editor's identity and their user level at the
time of the change. The solution also includes an internal notification mechanism informing users about changes to their records and extends the database schema to store the history of edits. The implementation was carried out as an addition to the existing web application without disrupting its original functionality.

The result of the work is an extended web system that enables secure collaboration between multiple transcribers, prevents data from being overwritten by users with insufficient permissions, and provides a transparent overview of changes to records. The benefits of the work include increased data consistency, better quality control of transcriptions, and a per-account notification flow that keeps long-term contributors aware of changes to their work.