summary

* AFAICT, this is not (yet) in active use in production YouTrack, which is still using https://github.com/JetBrains/xodus

* the technical leader of the YouTrackDB project, Andrii Lomakin, was one of the main contributors to OrientDB -- see https://medium.com/@youtrackdb

* YouTrackDB is a fork of OrientDB

* this project makes heavy use of Claude Code

* YouTrackDB does not use Kotlin

* this can be used as a network service (rather than just embedded in a single runtime process like in current production YouTrack), but I've not yet got the docker images working to try.

from the blurb

YouTrackDB is a general-purpose object-oriented graph database developed by JetBrains, used internally in production. It implements the Apache TinkerPop API with Gremlin query language support and features O(1) link traversal, schema-less/mixed/full modes, and encryption at rest. The project is a fork of OrientDB, re-architected under the com.jetbrains.youtrackdb package namespace.