Is there a way to play with this without using a credit card?
https://www.datomic.com/get-datomic.html starter version
https://github.com/tonsky/datascript Datascript is also neat, it's an in-browser DB with datalog query syntax. There's some neat stuff possible with om.next + datascript: https://github.com/omcljs/om/wiki/DataScript-Integration-Tut...