> ## Documentation Index > Fetch the complete documentation index at: https://aletyx.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # What is Drools? > Drools is the open-source business rules management system (BRMS) and inference engine at the heart of KIE, authoring rules in DRL, decision tables, or DMN. Drools is the open-source **business rules management system (BRMS)** and inference engine at the heart of the KIE ecosystem. It lets you express business policy as declarative rules — separated from application code — and evaluates them with a high-performance pattern-matching engine (based on the Rete algorithm). Rules can be authored in DRL (Drools Rule Language), decision tables, or the DMN standard. Aletyx ships an enterprise build of Drools with significant performance and tooling improvements. ## Where to go next Explore the Drools component and how Aletyx packages it for the enterprise. Stand up your first Drools project and run your first rules. Understand the Rete-based inference engine that evaluates your rules. Learn the Drools Rule Language used to author rules declaratively. Clear up how Drools relates to Kogito and the wider KIE ecosystem. See how rules fit into the decision automation architecture. Migrate older Drools 7.x applications to the modern platform.