QLever (pronounced "Clever") is a graph database implementing the RDF and SPARQL standards. QLever can efficiently load and query very large datasets, even with hundreds of billions of triples, on a single commodity PC or server. QLever outperforms other RDF/SPARQL databases by a large margin on most queries in a resourceful manner.
QLever implements the full SPARQL 1.1 standard, including federated queries, named graphs, the Graph Store HTTP Protocol, and updates. On top of its outstanding performance, QLever offers a variety of unique features: materialized views, advanced text-search capabilities, context-sensitive autocompletion of SPARQL queries, live query analysis, efficient spatial queries, and the interactive visualization of very large numbers of geometric objects on a map. QLever can also be used as an embedded database, that is, without the standard client-server setup but running in-process inside your own C++ code.
Here are demos of QLever on a variety of large datasets, including the complete Wikidata, Wikimedia Commons, OpenStreetMap, UniProt, PubChem, and DBLP. The largest dataset has over one trillion triples and runs on a single PC. The demos also feature QLever's context-sensitive autocompletion, which makes SPARQL query construction so much easier. The datasets are updated regularly. Click on "Index Information" for a short description (with dates) and basic statistics.
If you use QLever in your research work, please cite one of the following publications: our CIKM'17 paper (QLever's beginning, combination of SPARQL and text search), our CIKM'22 paper (QLever's autocompletion, with an extensive evaluation), our 2023 book chapter (survey of knowledge graphs and basics of QLever, with many example queries), our TGDK'24 article (the dblp knowledge graph and SPARQL endpoint), our SIGSPATIAL'25 paper (efficient spatial joins, with a performance evaluation against PostgreSQL+PostGIS), our ISWC'25 GRASP paper (zero-shot question answering on RDF graphs), and our ISWC'25 Sparqloscope paper (a comprehensive SPARQL benchmark with a performance comparison of QLever and several other RDF databases).
QLever is open source under the permissive Apache 2.0 license. QLever is in active and rapid development. If you find a bug or if you are missing a feature or if there is anything else you want to tell us, please open an issue or open a discussion.
To get started with QLever, use our native packages released for Debian, Ubuntu and macOS. Additionally, a platform-independent version of QLever is available as an image for Docker and Podman. Whether you use the native packages or the Docker/Podman image, everything related to QLever can be controlled via a single command-line tool qlever. Please refer to our Quickstart documentation for details.
For the official documentation, see docs.qlever.dev. Additional information (though potentially outdated) can be found on the QLever Wiki.