---
name: event-notifications-en-source
title: Registering event sources
description: An event source is a service or application on IBM Cloud that emits event notifications and publishes them to a topic within the Event Notifications service. A source is a registered entity in an Event Notifications service instance. A source can be registered to an Event Notifications service instance either as an **IBM Cloud source**, an **API source**, or an **IBM Cloud platform source**.
last-updated: 2026-08-04
---

> ## Documentation Index
> The table of contents for this documentation set is at https://cloud.ibm.com/docs/event-notifications?format=markdown
> The index for all IBM Cloud docs is at: https://cloud.ibm.com/docs/llms.txt
> Use these files to discover more information as needed.

# Registering event sources
{: #en-source}

An event source is a service or application on IBM Cloud that emits event notifications and publishes them to a topic within the Event Notifications service. A source is a registered entity in an Event Notifications service instance. A source can be registered to an Event Notifications service instance either as an **IBM Cloud source**, an **API source**, or an **IBM Cloud platform source**.
{: shortdesc}

A source can publish to multiple topics. In other contexts, sources are identified as producers or publishers.

From a billing perspective, ingested notifications are calculated for all incoming events. If you disable a source or if the source is not connected to a topic, you are not billed for the events from the IBM Cloud source. However, if the source is **Enabled**, and a topic is connected to it, the ingested events include all incoming events (not only the events that are filtered in the topic).
{: important}

## IBM Cloud sources
{: #en-ibm-sources-list}

The following IBM-provided sources are available:

- [Cloud Monitoring](https://cloud.ibm.com/docs/monitoring?topic=monitoring-eventnotif&format=markdown)
- [Security and Compliance](https://cloud.ibm.com/docs/workload-protection?topic=workload-protection-getting-started&format=markdown)
- [Cloud Logs](https://cloud.ibm.com/docs/cloud-logs?topic=cloud-logs-event-notifications-configure&format=markdown)
- [Cloud Projects](https://cloud.ibm.com/docs/secure-enterprise?topic=secure-enterprise-event-notifications-events&interface=ui&format=markdown)
- [Secrets Manager](https://cloud.ibm.com/docs/secrets-manager?topic=secrets-manager-event-notifications&interface=ui&format=markdown)
- [Toolchain](https://cloud.ibm.com/docs/ContinuousDelivery?topic=ContinuousDelivery-event-notifications-cd&interface=ui&format=markdown)
- [App Configuration](https://cloud.ibm.com/docs/app-configuration?topic=app-configuration-ac-int-en&format=markdown)
- [watsonx.data](https://cloud.ibm.com/docs/watsonxdata?topic=watsonxdata-event-notifications-events&format=markdown)
- [OpenPages](https://cloud.ibm.com/docs/openpages?topic=openpages-event-notifications-events&format=markdown)
- [IBM Cloud Backup for VPC](https://cloud.ibm.com/docs/vpc?topic=vpc-event-notifications-events&format=markdown)
- [Storage Ceph as a Service](https://cloud.ibm.com/docs/cephaas?topic=cephaas-event-notifications-events&format=markdown)

## API sources
{: #en-api-sources}

You can send custom events from your backend application to the Event Notifications service by using API sources. To do this, you must first add an **API source**.

To add an IBM Cloud source or an API source, see [Add an Event Notifications source tutorial](https://cloud.ibm.com/docs/event-notifications?topic=event-notifications-en-add-source&format=markdown).

## IBM Cloud platform sources
{: #en-ibm-cloud-platform-sources}

IBM Cloud platform sources are built-in sources that provide events from core IBM Cloud platform services.

- [IBM Cloud Platform Notifications](https://cloud.ibm.com/docs/support?topic=support-add-users-distribution-list&format=markdown#event-notifications-distribution-list)
- [IBM Cloud Resource lifecycle events](https://cloud.ibm.com/docs/event-notifications?topic=event-notifications-en-resource-lifecycle-events&format=markdown)

## Periodic timer source
{: #periodic-timer-source}

The Periodic timer is a built-in source that schedules events based on a user-defined time period. For more information, see [Periodic Timer](https://cloud.ibm.com/docs/event-notifications?topic=event-notifications-en-cron-periodic-timer&format=markdown).