The General Data Protection Regulation (GDPR) mandates that organizations maintain a comprehensive inventory of the data they hold on individuals. This requirement poses challenges within research institutes, where researchers traditionally have a high degree of autonomy in organizing their work.

Castellum addresses this by serving as a centralized repository, enabling researchers to disclose the individuals from whom they have gathered data. Additionally, Castellum allows to track recruitment consent for those individuals, thereby creating a recruitment pool for future research projects.



GDPR Compliance

Castellum is a central place where researchers disclose the individuals from whom they have gathered data, so that requests for access or erasure can be handled efficiently.

Pseudonym service

Contact details are stored in Castellum so all other databases can work with pseudonyms instead.


Castellum allows you to find potential participants from an existing pool using study specific filters.


You can manage appointments for test sessions.

What Castellum is not

Castellum itself is not meant to store any scientific data. It only stores information about which studies a subject has participated in as well as the corresponding pseudonyms.


There are only two notable exceptions to this rule: Study participations and recruitment attributes both contain traces of research data, but are required for the recruitment process.

Which features get integrated?

We often found it difficult to decide on levels of integration. Therefore, we want to provide some guidelines for future developers that should be considered before adding a new feature to Castellum:

  • Can the feature be decoupled from communication with subjects? For example we decided to integrate recruitment because it cannot be decoupled.

  • Would the new feature introduce different staff members (user groups) who would use Castellum only for this reason? For example, we decided against integrating a public relations view on current studies as it would have introduced staff members who otherwise have nothing to do with subject data.

  • Are there well established processes or tools that do not need to be replaced? Examples might include calendars or room management.

  • Are there established protocols to interface with the existing services instead of reimplementing them? For example, Castellum supports authentication via a central LDAP service.

  • Is it acceptable for users to integrate with external processes manually? For example, a pseudonym generated by Castellum would usually be entered into a MRI device by hand.

  • Is the feature preventing us from addressing the various needs of different research institutes?

Rather than applying these questions as strict rules we try to balance them within the process of reaching a decision.


Full installation instructions are available in the project repository.