myMdC: A Centralised Metadata Catalogue for Sustainable Data Management at European XFEL

Large-scale research facilities such as the European XFEL rely on multiple distributed services to manage complex experimental workflows. Consistent, reliable and timely metadata exchange between these services is essential to ensure automation and data integrity. This paper presents myMdC, the centralised metadata backbone that supports scientific data services in European XFEL. myMdC unifies and orchestrates metadata flows across core facility services, enabling interoperability and ensuring alignment with the facility's long-term data management strategy. In operation since the first day of user experiments in 2017, myMdC ensures real-time injection, documentation, and cataloguing of scientific datasets, forming the basis of data and metadata operations at European XFEL. Its integration with facility services enables immediate dataset tracking from acquisition through publication. It supports automation across the data inventory, control access during embargo periods, metadata preservation, Digital Object Identifier (DOI minting and integration of Findable, Accessible, Interoperable, and Reusable (FAIR) data workflows. By consolidating metadata management into a unified platform, myMdC facilitates scalable, transparent, and future-proof data practices, ensuring that scientific output remains robust and interoperable within the global research community.