When building BPMN workflows — whether in Flowable, Camunda, or any process engine — one of the first questions people ask is:
“What’s the difference between a User Task and a Service Task?”
While they may look similar in the model, their roles in the automation are completely different — and knowing when to use each is key to designing effective, human-centric or system-driven workflows.
🧍♂️ User Task = Human Work
A User Task represents work that must be done by a human.
✅ Common examples:
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Approve a request
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Fill out a form
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Review a document
👀 In Flowable, User Tasks are typically shown in the task inbox (or external app) and assigned to a user or group.
🛠 How it works:
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The task waits until a user claims and completes it
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You can assign users dynamically with expressions
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You can attach forms, due dates, priority, and listeners
🤖 Service Task = System Work
A Service Task is used for automated work — things the system can do without human input.
✅ Common examples:
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Call a REST API
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Execute a script
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Run Java logic
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Send an email
🛠 How it works:
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Executes instantly when reached
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Can be configured using:
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Delegate classes or expressions (
${beanName}) -
REST connectors
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External scripts
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In Flowable, Service Tasks are often connected to Spring beans or integrated services.
🔁 How They Work Together
A good BPMN process often alternates between user-driven and system-driven tasks.
🔄 For example:
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User fills out a form (User Task)
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System validates data and calls an API (Service Task)
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Manager reviews result (User Task)
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System sends confirmation email (Service Task)
📌 The power of BPMN is in orchestrating these steps clearly and efficiently.
❗ Quick Summary:
| Feature | User Task | Service Task |
|---|---|---|
| Executed by | Human | System |
| Waits for input | Yes | No |
| Common uses | Approvals, data entry | API calls, logic, automation |
| Needs UI | Yes (form, inbox, app) | No |
🎯 Pro Tip:
Use User Tasks for anything that involves a decision, input, or action from a person.
Use Service Tasks to keep things fast, repeatable, and error-free with automation.
Have you faced challenges deciding between User and Service Tasks in your workflows? Let’s share tips and real-world examples to help the community model smarter.
#BPMN #Flowable #Automation #UserTask #ServiceTask #ProcessDesign #WorkflowAutomation #LowCode #AKITIInstitute
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