[blintzing]

I was very interested, but pretty disappointed that Datomic is completely closed source. Maybe this is a little mean, but what could be more "simple" than being able to read, understand, and modify the database you rely on?

Neo4j, though marketed differently, is a similar approach (but the Community version is GPLv3 and Enterprise is AGPLv3). The Cypher query language is declarative in a similar way to Datomic - the biggest missing feature is transactions.

[joshdick]

Rich Hickey has been criticized for that repeatedly. When asked, he's been transparent that Datomic is closed source so that he can put his kids through college. He also points out that he already gave us the whole Clojure language open source.

It's hard for me not to sympathize with him on this.

[brianwawok]

For sure, I would have played around with it, if it was open source and free to some small number of clients. But with so many FOSS databases, why use Datomic?