Datomic's "immutable database + Datalog" was definitely the biggest source of inspiration but XTDB has a lot of differences - I wrote this FAQ entry up a few ye

Datomic's "immutable database + Datalog" was definitely the biggest source of inspiration but XTDB has a lot of differences - I wrote this FAQ entry up a few years back: https://docs.xtdb.com/resources/faq/#comparisons https://docs.xtdb.com/resources/faq/#comparisons (note this comparison is for XTDB 1.x and Datomic On-Prem only, so needs revisiting!) Arguably the biggest difference is that XTDB has a schemaless, dynamic core. Having a sane schema is of course important when building complex things, but we believe that the flexibility to experiment with schema (fully) in userspace is essential for moving the state of the art forwards. For instance a lots Clojure users these days prefer relying on https://github.com/metosin/malli https://github.com/metosin/malli for _all_ their schema needs.