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Version: 3.4.x

Timer Start Event (Interrupting)

A Timer Start Event initiates a process instance based on a specified time or schedule.


Please note that a process definition version can accommodate only one Timer Start Event.


If a process definition contains versions with Start Timer Event nodes, only for the published version will generate a scheduler.


Depending on the node type, the following timer types can be configured:

Node TypeDateDurationCycle
Timer Start EventYesNoYes

Starting a process via registered timers requires sending a process start message to Kafka, necessitating a service account and authentication. For detailed guidance, refer to:

Service Accounts

Timer Type Values

  • Date
  • Cycle


Specifies an exact date and time for triggering the event. You can use ISO 8601 date format for accurate date-time representation.

Scenario: Employee Onboarding Reminder

In this scenario, the Timer Start Event is used to trigger an employee onboarding process at a specific date and time.

  • Start Event (Timer Start Event) - New Hire Start Date
    • Timer Definition: 2023-09-01T09:00:00Z (ISO 8601 format) → This means the process will initiate automatically at the specified date and time.
    • This event serves as the trigger for the entire process.
    • Transition: → Employee Onboarding Notification
  • Employee Onboarding Notification
    • Notify new employee about onboarding requirements by sending an email notification with a template called "Important Onboarding Information"
    • Actions: The HR team or automated system sends out necessary email information/documents, and instructions to the new employee.
    • After the notification is sent, the process transitions to the Complete Onboarding node.

  • Complete Onboarding
    • Employee onboarding completed
    • At this point, the employee's onboarding process is considered complete.
    • Actions: The employee may have completed required tasks, paperwork, or orientation sessions.


Specifies a repeating interval for triggering the event. The cycle can be defined using ISO 8601 repeating intervals or cron expressions.

Configuration According to Timer Type

For each timer type, the following values can be configured:

FieldValidationsAccepted Values
DefinitionMandatory- Process param
- ISO 8601 formats (date/duration)
- Cron expressions (cycle)
Start TimeOnly for Cycle- ISO 8601 format (date-time)
- Process param
End TimeOnly for Cycle- ISO 8601 format (date-time)
- Process param
Active/ SuspendedDefault: Suspended- Active
- Suspended

The Start Timer Event supports either ISO 8601 formats or spring cron expressions for defining timer values.

General Rules

  • A process definition version can have a single published version, which can be a committed or a WIP version.
  • Only the published version generates a scheduler when it contains Start Timer Event nodes.
  • When a new committed version is published or when a WIP published version is updated with new Start Timer Event settings:
    • The scheduler is updated based on the settings in the published version.
    • The scheduler state (active or suspended) remains the same as before.

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