FAIRness of research data largely depends on the availability of rich and standardized metadata. While such metadata is commonly available at the study level, fine-grained metadata, especially for tabular scientific data, is often lacking (Wenzig/Han 2024). In a project funded by KonsortSWD-NFDI4Society, three research data centers (SOEP, LIfBi, and DZHW) investigate what is required to convert existing metadata into a standardized format and publish it using a common protocol.