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QLever

A SPARQL engine capable of querying very large knowledge graphs (including complete Wikidata) on a single machine. Implements full SPARQL 1.1 with autocompletion and text search.

Visit website GitHub 893 stars
Overall rank
#10
First released
November 2017
License
Apache-2.0
Built with
C++

Details

Vendor
University of Freiburg
Type
RDF
Category
Emerging
License
Apache-2.0
Language
C++
Query Languages
SPARQL
Protocols
HTTP/RESTSPARQL Protocol
Sources 5 references

Protocols SPARQL Protocol, HTTP/REST

QLever implements SPARQL 1.1 Protocol plus the Graph Store HTTP Protocol; it also exposes a separate, documented non-SPARQL admin HTTP API on the same host:port (e.g. cmd=rebuild-index, cmd=... commands, distinct from query=/update= SPARQL requests), which is genuine HTTP/REST beyond the SPARQL endpoint — pass_B's inclusion of HTTP/REST is correct and pass_A's SPARQL-only answer misses this admin surface.

  • QLever implements the full SPARQL 1.1 standard, including federated queries, named graphs, the Graph Store HTTP Protocol, and updates.
    QLever README · reviewed 2026-08-02
  • Alternatively, you can trigger the rebuild via the QLever HTTP API as described below.
    Rebuild index - QLever Documentation · reviewed 2026-08-02

Released 2017-11

Refined from year-only 2017 to month: QLever was first published and presented at CIKM'17, held November 6-10, 2017; the GitHub repository's 2014 creation date is only a development floor, not the public release.

Language C++

Matches current value; confirmed by GitHub language statistics (98.1% C++) and the project's own README.

  • 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.
    ad-freiburg/qlever · reviewed 2026-08-02

License Apache-2.0

SPDX identifier as classified by GitHub from the repository licence file.