Drools

Drools is an open-source Business Rule Management System (BRMS) using an enhanced Rete algorithm for forward and backward chaining rules processing. Started in 2001 by Bob McWhirter, it joined JBoss/Red Hat in 2005-2006, and entered the Apache Incubator in January 2023 as part of the KIE community. Red Hat productized it as Red Hat Decision Manager (formerly Red Hat JBoss BRMS). Widely used in enterprise Java applications for policy automation.