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Activity Multi-Instance

An Activity Multi-Instance is a BPMN activity configuration that allows an activity to be executed multiple times for a collection of items. It is used to model repeated execution of the same activity, either sequentially or in parallel, based on defined loop characteristics.

Multi-instance behavior can be applied to tasks and subprocesses.

Key characteristics​

  • Multiple executions of the same activity:
    The activity is executed once for each element in a defined collection.

  • Sequential or parallel execution:
    A Multi-Instance activity can be configured to execute:

    • Sequentially: instances are executed one after another.
    • In parallel: all instances are executed at the same time.

  • Collection-based:
    The number of instances is determined by a collection or an expression evaluated at runtime.

  • Shared activity definition:
    All instances share the same activity definition but have their own execution context.

  • Completion condition (optional):
    The activity may define a completion condition that allows the multi-instance execution to finish before all instances complete.

  • Applicable to multiple activity types:
    Multi-instance behavior can be applied to Tasks and Subprocesses.

Execution behavior​

  • For parallel multi-instance, multiple tokens are created, one for each instance.
  • For sequential multi-instance, a single token is reused to execute instances one after another.
  • The activity completes when:
    • all instances finish, or
    • the defined completion condition evaluates to true.

Supported activity types​

Multi-instance behavior can be applied to the following activity types:

  • Task
  • UserTask
  • ServiceTask
  • SendTask
  • ReceiveTask
  • BusinessRuleTask
  • ScriptTask
  • ManualTask
  • SubProcess
  • CallActivity

Graphical notation​

A standard activity shape with a multi-instance marker at the bottom center:

  • Three vertical lines: parallel multi-instance

Parallel Multi-instance usage example

  • Three horizontal lines: sequential multi-instance

Horizontal Multi-instance usage example

XML Definition​

Parallel multi-instance example​

<bpmn:userTask id="ReviewTask" name="Review Document">
  <bpmn:multiInstanceLoopCharacteristics isSequential="false">
    <bpmn:loopCardinality>5</bpmn:loopCardinality>
  </bpmn:multiInstanceLoopCharacteristics>
</bpmn:userTask>