Camunda 7 Architecture – Complete Overview

🚀 Introduction

Camunda 7 is a powerful open-source platform for workflow and decision automation, widely used in enterprise Java applications.
It allows you to model, execute, and monitor BPMN workflows, DMN decisions, and CMMN case management within your existing tech stack.

In this blog, we’ll explore the Camunda 7 Architecture — its core components, how they interact, and how developers can integrate it into their systems.

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🧱 High-Level Architecture

Camunda 7 is based on a three-layer architecture:

1️⃣ Process Engine (Core Runtime)
2️⃣ Web Applications (Cockpit, Tasklist, Admin)
3️⃣ External Systems & Integration APIs

Each layer plays a specific role in the automation lifecycle — from defining BPMN processes to executing them and visualizing their state.

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⚙️ 1. Process Engine (Core Runtime)

The Process Engine is the heart of Camunda 7.
It executes BPMN workflows, DMN decision tables, and manages process states.

🔹 Key responsibilities:

• Parsing and deploying BPMN / DMN models

• Executing process instances

• Managing user and service tasks

• Handling events, timers, and gateways

• Storing runtime data in relational databases

The engine can run in two ways:

Mode	Description
Embedded Engine	Runs inside your Java / Spring Boot application. Ideal for microservices.
Shared Engine	Runs as part of a central container (e.g., WildFly, Tomcat). Applications connect via REST or Java API.

Embedded Process Engine

Process Engine Architecture

Shared, Container-Managed Process Engine

Standalone (Remote) Process Engine Server

🧠 Technologies used:

• Java-based runtime

• Persistence layer via JPA / MyBatis

• Transaction management integrated with the Java EE container

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🖥️ 2. Web Applications Layer

Camunda 7 ships with three main web apps built on top of the Process Engine REST API:

Web App	Purpose
Cockpit	For administrators and developers to monitor and analyze running and completed process instances
Tasklist	For end users to view and complete their assigned user tasks
Admin	For managing users, groups, and authorizations

These applications interact with the Process Engine through the REST API, allowing real-time tracking and management.

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🔗 3. Integration Layer (APIs and External Systems)

Camunda provides multiple ways to integrate with external applications:

🔸 Java API

You can directly interact with the process engine inside your application:

ProcessEngine engine = ProcessEngines.getDefaultProcessEngine();
RuntimeService runtimeService = engine.getRuntimeService();
runtimeService.startProcessInstanceByKey("invoiceProcess");

🔸 REST API

Allows communication from non-Java systems:

POST /engine-rest/process-definition/key/invoiceProcess/start

🔸 External Task Pattern

Microservices can fetch and complete tasks asynchronously via:

GET /engine-rest/external-task/fetchAndLock

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🗄️ 4. Database Layer

Camunda 7 stores its runtime data and history in a relational database (e.g., PostgreSQL, MySQL, Oracle).

Table Category	Description
Runtime Tables	Active process instances, user tasks, variables
History Tables	Completed instances, audit logs, events
Deployment Tables	Deployed BPMN / DMN definitions

All state transitions are persisted through ACID-compliant transactions, ensuring data consistency.

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🧠 5. Camunda 7 Core Components (Summary Diagram)

Architecture Overview:

 ┌─────────────────────────────────────────────────────┐
 │                  Web Applications                    │
 │ ┌──────────┐  ┌──────────┐  ┌──────────┐             │
 │ │ Cockpit  │  │ Tasklist │  │ Admin    │             │
 │ └──────────┘  └──────────┘  └──────────┘             │
 │          │           │           │                   │
 └──────────┼───────────┼───────────┘                   │
            │           │                               │
            ▼           ▼                               │
      ┌────────────────────────────┐                    │
      │       REST / Java API      │                    │
      └──────────────┬─────────────┘                    │
                     │
           ┌────────────────────────┐
           │     Process Engine      │
           │  (BPMN / DMN Execution) │
           └──────────┬──────────────┘
                      │
         ┌────────────────────────────┐
         │       Database Layer        │
         │ (Runtime + History Tables)  │
         └────────────────────────────┘

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🌐 6. Typical Deployment Options

Option	Description
Standalone Server	Deploy Camunda as a web application on Tomcat / WildFly
Spring Boot Starter	Simplifies integration with Spring ecosystem
Docker Container	Official Camunda Docker images available on Docker Hub

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🔍 7. Example: BPMN + DMN in Camunda

• BPMN: Defines the process flow — Start → User Task → Service Task → End

• DMN: Defines business decisions — “If invoice > 5000 → Needs Manager Approval”

BPMN references DMN through a Business Rule Task, enabling externalized decision logic.

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🎯 Conclusion

Camunda 7 Architecture provides:

• A lightweight Java process engine

• Flexible integration APIs

• Powerful monitoring tools

• Seamless database persistence

It’s perfect for enterprises that need transparency, automation, and scalability across their business workflows.

🧩 Camunda 7 = BPMN for workflows + DMN for decisions + APIs for integration.

💼 Professional Support Available

If you are facing issues in real projects related to enterprise backend development or workflow automation, I provide paid consulting, production debugging, project support, and focused trainings.

Technologies covered include Java, Spring Boot, PL/SQL, Azure, and workflow automation (jBPM, Camunda BPM, RHPAM).

📧 Contact: ishikhanirankari@gmail.com | info@realtechnologiesindia.com

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