The proliferation of digital scientific data and products necessitates robust management and cataloguing systems to ensure compliance with the FAIR principles (Findable, Accessible, Interoperable, Reusable). Standardised metadata associated with datasets form the bedrock for achieving this objective. This technical report introduces MetaCat, a specialised backend service developed to address the challenge of metadata management, serving exclusively as a Metadata Catalog. Conceived to be agile and lightweight, MetaCat rigorously implements the DataCite Metadata Schema (v4.6) standard, decoupling metadata management from the physical data storage. The system exposes a pragmatic, REST-like, API-first architecture for Create, Read, Update, and Delete (CRUD) operations on metadata...