Another interesting project in the same space is DGraph (https://github.com/dgraph-io/dgraph), built by a former Google employee who worked on Knowledge Graph and thus likely a former colleague of the author of Cayley.
A interesting feature of DGraph (vs Cayley) is that instead of using its own query language it uses a language based on Facebook's GraphQL.
A interesting feature of DGraph (vs Cayley) is that instead of using its own query language it uses a language based on Facebook's GraphQL.