the main difference is that datahike also stores transaction history, and is not, although it can be, schemaless

Thank you!

Let me add to this that we have full persistent semantics, that is you can get a snapshot of the database for free and pass it around in your app between requests or to a background batch processing job. Datalevin's indices are only snapshotted inside of a LMDB transaction and are mutated as soon as your query result has returned. Datahike is like Datomic, while Datalevin is a mutable Datalog database. Having said this it is my belief that Datalevin could have been realized inside of Datahike with the interfaces we provide to integrate new indices.

thank you! that clarifies things quite a bit