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Service task

A Service Task is a BPMN flow element that represents work performed automatically by a system, without human involvement. It automates process steps by invoking external services, APIs, or backend systems.

Key characteristics​

  • Automated execution: A Service Task executes automatically without requiring human interaction. It invokes an external service and waits for the result.

  • Can have incoming and outgoing sequence flows: Service Tasks connect to other flow elements via sequence flows, allowing complex workflows with conditional routing based on service outcomes.

  • Input and output parameters: Service Tasks can receive data from the process and return data back to continue execution with service-provided information.

  • Implementation types: Service Tasks can invoke different types of implementations (HTTP calls, web services, scripts, etc.) based on configuration.

  • Error handling: Service Tasks support error handling through boundary events and fault responses when service calls fail.

  • Types of service task handling:

    • HTTP/REST invocation: Calls external REST APIs or HTTP endpoints. Sends request data and processes the response to continue execution.

    • SOAP web service: Invokes SOAP-based web services with XML payloads. Suitable for enterprise system integration.

    • Message-based: Sends a message to an external system and waits for a correlated response or acknowledgment.

    • Script execution: Executes server-side scripts or expressions to perform calculations, data transformations, or business logic.

    • Database operations: Executes database queries, updates, or stored procedures to interact with data systems.

    • External worker pattern: Delegates work to external worker applications that subscribe to task types and handle execution asynchronously.

    • System integration: Integrates with third-party systems, microservices, or legacy systems through adapters or connectors.

Graphical notation​

Service task usage example

A rectangle with a gear icon in the top-left corner.

XML Definition​

<bpmn:serviceTask id="ServiceTask_1" name="Process Payment">
  <bpmn:incoming>Flow1</bpmn:incoming>
  <bpmn:outgoing>Flow2</bpmn:outgoing>
</bpmn:serviceTask>

Current Implementation​

Service task is fully supported.