Event Listeners

Introduction

Event Listeners is a Catalyst Cloud Scale component that functions as an event bus service, listening for predefined events and automatically triggering the corresponding Event functions or targeted Circuits. It’s particularly useful for automating recurring tasks or workflows that are tied to specific events within your application. With the event-driven architecture powered by Catalyst, this component helps ensure reliable, real-time execution of actions whenever those events occur.

Note: Catalyst now offers you a brand new event bus service called Signals. This service is a significant upgrade to the current Cloud Scale Event Listeners component. You can find out more about the Catalyst Signals service here.

Catalyst Event Listeners also allow you to transport a stream of real-time data from various Catalyst components in the application, or from custom sources, to the functions that are invoked as a result. You can associate rules with an event listener and define the exact source to listen to for events, and the actions to be taken upon their occurrence.

There are three types of Catalyst Event Listeners:

  1. Catalyst Component Event Listener: The Catalyst component event listener can link an event that occurred in one of your Catalyst components to the execution of a target event function or circuit. This is created by default.
  2. Custom Event Listeners: You can create custom event listeners which function differently from the Catalyst component event listener. When you create a custom event listener in Catalyst, a URL is automatically generated for it. Whenever this URL is invoked by the end user, this event listener triggers the execution of the target event function or circuit.
  3. Zoho Events: You can also create Zoho event listeners that listen for and capture events occurring in other Zoho services that you have configured, such as Zoho CRM. These event listeners will get invoked every time a specific, associated event in the external service occurs, and Catalyst will execute the target event function or circuit as a result.

You can access and configure event listeners for your project from the Catalyst console. The console also provides statistics on the performance of each of your event listeners, details of queued events, and drilled-down execution history for every rule of an event listener. You can also see a sample pattern of the data that will be sent to the target function or circuit for every rule.

Catalyst also provides you with the flexibility to create application alerts for event listeners directly from the Event Listeners’ Rules section in the console, instead of navigating to the Application Alerts component.

Note: You will not be able to configure or work with event listeners from the CLI or using the SDKs. However, you can generate sample payloads for both component and custom event sources in the CLI, and test event functions in the local environment. Refer to the Event Generate help page to learn more.

Last Updated 2025-06-27 13:38:50 +0530 +0530

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