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Event & Triggers allow executing an event after or before executing a specific node. This helps to reduce the steps of a flow that are not related to the actual business process such as logging, internal error notification sending, etc. improving the clarity.
For example, if you want to write a notification after retrieving data from a REST API in a flow, you can assign it as an event instead of adding an additional node to write notifications.

Events
If you click on a node that supports events, you will see the Events tab with two events.

- On After: An event can be defined after a specific execution
- On Before: An event can be defined before a specific execution
The events are supported on the following nodes:
Flow Nodes
Action nodes such as
- Expression
- Sub-Flow
- DRD
- Validator
- DT
- NL
- IRL
- REST API
Lifecycles
- Start
- End
- Throw
- Terminate
- Restart
DRD Nodes
- Decision
- Business Knowledge
- Sub-DRD
Triggers
These are the triggers that can be invoked on an execution:
- CallFlow: Call a flow
- CallDecisionTable: Call a Decision Table
- CallNaturalLanguage: Call a Natural Language document
- Notification: Create a notification
- MultiExpression: Execute a set of expressions
- Expression: Execute an expression
- SendEmail: Send an email
- API (REST): Call a REST service
- Database: Connect to a database and perform query actions

Example
The following example shows how to send a notification after a REST API call using an event. The sample project is attached at the end of the page.
There we have set the Notification as the On After event of the REST API node.

Notification is set to display one of the arguments from the response of REST API.

Once the flow is executed, the notification can be seen.
