Hey, look what’s been open-sourced: AWS Event Ruler! Check out the announcement blog. I built v1.0 of this Java library while I was at AWS, and wrote about it in Filtering Lessons. Tl;dr: It offers APIs for declaring pattern-matching Rules, as many as you like, then for presenting data records called Events and finding out which Rules each Event matches, very quickly. It’s in production in multiple Amazon (not just AWS) services, notably EventBridge. Also see: Content-based Filtering...