ICOS has developed its own metadata model and ontology to describe all the digital objects it manages, and the relationships between them – not only data but also people, measurement stations, instruments, etc. The metadata is stored as time-stamped assertions (“triples”) expressed in RDF (Resource Description Framework), together with the metadata model itself. The open SPARQL endpoint gives full read access to this ICOS ontology based metadata repository and is meant for direct machine to machine operation. The main target audience for this service is IT developers and IT-savvy researchers who wish to implement programmatic queries of the ICOS metadata, for example to retrieve up-to-date information about ICOS digital objects for use in data analysis scripts. Supported output formats include JSON, CSV, XML and TSV/Turtle. For more information about ICOS metadata, visit our GitHub “meta” repository at https://github.com/ICOS-Carbon-Portal/meta.