Ringgaard Research ApS is a not-for-profit company that develops and maintains the SLING system as well as doing research relating to knowledge management and natural language processing.
SLING is an open source project under an Apache license and all the code is available on GitHub. SLING is written mostly in C++ but can be used from Python by using the SLING Python API (pysling).
The SLING knowledge base contains approximately two billion facts about 100 million entities. Every day a new knowledge base is built from Wikidata as well as a number of other information sources.
SLINGDB is a lightweight persistent key-value database with a HTTP interface. It can be installed independently of the other SLING components and is distributed as a standalone Debian package.