> ## 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.
# Event-Driven Architecture
> Build event-driven rules, DMN decisions, and BPMN processes with Kogito on Quarkus, using out-of-the-box Apache Kafka and CloudEvents integration for event routing.
## Event-Driven Architecture with Aletyx Enterprise Build of Kogito and Drools 10.1.0-aletyx in Quarkus
Modern applications thrive on real-time data and responsiveness—needs perfectly addressed by **Event-Driven Architecture (EDA)**. Instead of tightly coupling services, EDA relies on loosely connected components that produce and react to events, thus enabling scalability, resilience, and flexibility in cloud-native environments.
**Kogito** leverages the power of Drools (rules), jBPM (processes), and DMN (decisions) to provide a **next-generation business automation toolkit**. When running on **Quarkus**, a Kubernetes-native Java framework, Kogito services start quickly, use minimal memory, and seamlessly integrate with **Apache Kafka** out of the box. Below, we explore how Kogito’s rules, decisions, and processes interact through **CloudEvents**, enabling both message consumption and production without extra glue code.
## Out-of-the-Box Kafka and CloudEvents Integration
Kogito natively supports **Kafka** with minimal configuration. By default, it **consumes** and **produces** events following the **CloudEvents** standard, embedding metadata such as `type` and `source` to ensure the correct Kogito component receives each event. This means:
* **Rules** typically expect `type="RulesRequest"` .
* **DMN** expects `type="DecisionRequest"` , `kogitodmnmodelnamespace` , and `kogitodmnmodelname` .
* **Processes** match events based on the **type** specified in their **message node** definitions.
Even when multiple services share a single Kafka topic, CloudEvents metadata ensures proper routing to the correct engine or workflow node, drastically reducing boilerplate routing logic.
## Event-Driven Rules (DRL)
[
](/docs/images/architecture/core/processes/advanced-bpmn/images/drl-eda.png)
When building event-driven rules, **Drools** in Kogito continuously listens for relevant events in a specified topic:
1. An event arrives with `type="RulesRequest"` .
2. Kogito inserts the payload as a fact into the Drools session.
3. All matching rules are evaluated (or “fired”).
4. When a rule triggers, new facts can be asserted, and a **resulting event** can be produced to a Kafka topic.
## Event-Driven Decisions (DMN)
[
](/docs/images/architecture/core/processes/advanced-bpmn/images/dmn-eda.png)
For **Decision Model and Notation (DMN)** use cases, Kogito listens for events with `type="DecisionRequest"`, expecting the **namespace** (`kogitodmnmodelnamespace`) and **model name** (`kogitodmnmodelname`). Upon receiving such an event:
1. Kogito routes the payload to the correct DMN model based on the namespace and name.
2. The DMN engine evaluates the incoming data against your decision logic.
3. The decision result is either returned synchronously or published as a CloudEvent to another Kafka topic.
## Event-Driven Processes
[
](/docs/images/architecture/core/processes/advanced-bpmn/images/bpmn-eda.png)
Kogito’s **jBPM-based process engine** provides **event-driven processes** that start or proceed upon receiving a CloudEvent:
1. A message matches the **type** defined in the **message node** in your BPMN process.
2. Kogito injects the data into the process context.
3. The process executes its tasks or sub-processes in sequence.
4. At key points, the process can produce new events that trigger actions in other services.
## Conclusion
Together, **Kogito** and **Quarkus** provide a robust, cloud-native platform for building **event-driven** services that incorporate **rules**, **decisions**, and **processes**. By leveraging **Kafka integration** out of the box, you can develop scalable, maintainable, and responsive event-driven applications with minimal boilerplate. Whether you are streaming data for rules evaluation, orchestrating business workflows, or automating decisions, Kogito on Quarkus offers a powerful toolkit to handle events from start to finish.