The NFDI4Earth Knowledge Hub is a core backend service of NFDI4Earth, providing centralized, structured access to metadata on all NFDI4Earth resources. It enables you to discover, access, and integrate semantic resources relevant to Earth System Sciences (ESS), supporting FAIR and open workflows in your research and services. It facilitates exploring and querying structured metadata on datasets, services, tools, educational materials and standards relevant to ESS by providing a SPARQL endpoint, under https://sparql.knowledgehub.nfdi4earth.de/.