activities

Sub-Process

A Sub-Process is a compound activity containing its own complete flow of activities, gateways, and events. It encapsulates related steps, enabling process decomposition and reuse.

Category
activities
BPMN Spec
Section 10.2.4
Icon Class
bpmn-icon-subprocess-expanded

What is a Sub-Process?

A Sub-Process (or Embedded Sub-Process) contains a complete BPMN flow within it-activities, gateways, events, and sequence flows. It groups related activities together, providing scope for variables and event handling.

Visual Representation

A Sub-Process displays as a large rounded rectangle with a small plus sign at the bottom center when collapsed, or shows its internal contents when expanded. The border is thicker than regular tasks.

Key Characteristics

  • Contains complete flow: Has its own start event, activities, and end event(s)
  • Variable scope: Can define local variables visible only within the sub-process
  • Event scope: Boundary events can attach to handle sub-process-level exceptions
  • Visual grouping: Organizes related activities for readability

Trigger Variants

Sub-Process can be triggered by different mechanisms. Each variant uses a specific icon marker to indicate its trigger type.

Common Use Cases

Order Fulfillment Phase

Group all fulfillment activities (pick, pack, ship) into a sub-process that can have its own error handling.

Approval Workflow

Encapsulate the multi-step approval flow so boundary events can handle escalation at the approval level.

Repeatable Section

Mark a sub-process as multi-instance to execute the same steps for each item in a collection.

Frequently Asked Questions

Related BPMN Elements

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