Event-Based Gateway
An Event-Based Gateway routes based on which event occurs first. It creates a race condition where the first catching event to trigger determines the path taken. For example, after sending an invoice, the gateway waits for either a payment confirmation message or a 30-day timeout — whichever arrives first decides whether to proceed with fulfillment or escalate to collections.
What is an Event-Based Gateway?
An Event-Based Gateway models a decision point where the next step depends on which event happens first. Unlike data-based gateways, it routes based on events rather than process data.
Visual Representation
An Event-Based Gateway shows a diamond shape containing a pentagon inside a circle. The pentagon represents multiple catching events that are racing.
Key Characteristics
- Event racing: First triggered event wins
- Exclusive activation: Only one following event path activates
- Catch events follow: Must be followed by catching intermediate events
- Response or timeout: Commonly used for message-with-timeout patterns
See it in action
The bank waits for either a confirmation or a timeout — whichever comes first
Read: Bankovia →Common mistake
Placing activities directly after an Event-Based Gateway. Only catching events (Message, Timer, Signal, Conditional) and Receive Tasks can follow an Event-Based Gateway.
How it connects
Common Use Cases
Response Timeout
Wait for either customer response message or 48-hour timeout-whichever happens first determines the path.
Competing Channels
Wait for acceptance via either email link click or mobile app confirmation.
External Decision
Wait for either approval signal or rejection signal from an external system.
Frequently Asked Questions
Related BPMN Elements
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