Blazegraph uses SPARQL
Blazegraph is an open source triplestore and graph database, developed by Systap, which is used in the Wikidata SPARQL endpoint and by other large customers. It is licensed under the GNU GPL (version 2).
Amazon acquired the Blazegraph developers and the Blazegraph open source development was essentially stopped in April 2018.Prominent users
The Wikimedia Foundation uses Blazegraph for the Wikidata Query Service, which is a SPARQL endpoint.
The Datatourisme project uses Blazegraph as the database platform; however, GraphQL is used as the query language instead of SPARQL.