Cayley is an open-source database for Linked Data. It is inspired by the graph database behind Google's Knowledge Graph (formerly Freebase).

• Built-in query editor, visualizer and REPL
• Multiple query languages:
  • Gizmo: query language inspired by Gremlin
  • GraphQL-inspired query language
  • MQL: simplified version for Freebase fans
• Modular: easy to connect to your favorite programming languages and back-end stores
• Production ready: well tested and used by various companies for their production workloads
• Fast: optimized specifically for usage in applications

Rough performance testing shows that, on 2014 consumer hardware and an average disk, 134m quads in LevelDB is no problem and a multi-hop intersection query -- films starring X and Y -- takes ~150ms.

• Website: cayley.io
• Slack: cayleygraph.slack.com -- Invite here
• Discourse list: discourse.cayley.io (Also acts as mailing list, enable mailing list mode)
• Twitter: @cayleygraph
• Involvement: Contribute