Drasi: Microsoft's open source data processing platform for event-driven systems

In 2014, we built a similar type event-driven system (but specifically for document distribution (a document can be distributed to a target set of entities; if a new entity is added, we need to resolve which distributions match)) and also ended up using Cypher via Neo4j (because of the complex taxonomical structure of how we mapped entities).

It is a super underrated query language and while most of the queries could also be translated to relational SQL, Cypher's linear construction using WITH clauses is far, far easier to reason about, IMO.

EDIT: feel like the devs went overboard with the mix of languages. Shoehorned in C# Blazor? Using JS and Jest for e2e testing?

[0] https://drasi.io/reference/query-language/