--- schema_version: "1" id: 690b420f7520d35d0ef8221bc8198f1bd2adab7fdb9ecef7650d32f7a693be31 title: Event Channels collection: admin version: current locale: en-us portal_url: https://docs.salesforce.com/admin/current/en-us/platform/264-0-0/ev_relay_components.md canonical_url: https://help.salesforce.com/s/articleView?id=platform.ev_relay_components.htm&release=264.0.0&type=5 source_site: help.salesforce.com content_type: documentation content_hash: 334f8ea6584713b490638ee700657dcec19d85be5240aec591d804a356905a85 description: An event relay uses an event channel. A channel is a stream of events in the Salesforce event bus. A single channel can contain multiple types of platform events, including real-time event monitoring events, or change data capture events. products: - Salesforce Platform - Security release: "264" --- # Event Channels An event relay uses an event channel. A channel is a stream of events in the Salesforce event bus. A single channel can contain multiple types of platform events, including real-time event monitoring events, or change data capture events. Each event relay is associated with a unique channel that’s identified by its channel ID. Don’t reuse a channel for another event relay. ![Tip](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-platform-extend_click-264-0-0-production-enus/5f7d9219-b7b1-4552-8891-f1aba9b289fc/images/icon_tip.png) Tip To stream the same type of event to different AWS regions, create a separate channel for each AWS region, and then create an event relay for each channel. ## Custom Channels for Platform Events and Change Events Use a custom channel to group event messages from one or more events through channel members. For example, for platform events, if `MyEvent1__e` is a custom platform event defined in Salesforce, create a channel to receive event messages for `MyEvent1__e` if you add a channel member for `MyEvent1__e`. To receive event messages for another event on that channel, such as `MyEvent2__e`, add a channel member for `MyEvent2__e`. ![Tip](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-platform-extend_click-264-0-0-production-enus/5f7d9219-b7b1-4552-8891-f1aba9b289fc/images/icon_tip.png) Tip If you’re using a custom platform event, make sure that platform event is defined in Salesforce. For more information, see [Platform Event Fields](https://developer.salesforce.com/docs/atlas.en-us.platform_events.meta/platform_events/platform_events_define_ui.htm) in the Platform Events Developer Guide. For the maximum number of custom channels that you can create for custom platform events and real-time event monitoring events, see [Common Platform Event Allocations](https://developer.salesforce.com/docs/atlas.en-us.platform_events.meta/platform_events/platform_events_limits_common.htm) in the Platform Events Developer Guide. Similarly, for change data capture, you can create a custom channel to receive change event messages. If you create a channel for changes in one Salesforce object, such as `AccountChangeEvent`, the channel contains one member for `AccountChangeEvent`. To receive events for another Salesforce object, such as `LeadChangeEvent`, add another channel member. ![Tip](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-platform-extend_click-264-0-0-production-enus/5f7d9219-b7b1-4552-8891-f1aba9b289fc/images/icon_tip.png) Tip Salesforce provides change events, so you don’t define them. For more information about creating custom channels, see [Create a Channel and Channel Members](https://help.salesforce.com/s/articleView?id=platform.ev_relay_create_channel_section.htm&release=264.0.0&type=5 "You can create a channel and add members by using Tooling API. A channel is a stream of events. It contains members that specify the type of events that can be received on the channel. A channel can contain a stream of platform events, including real-time event monitoring events, or change data capture events. For a channel of change data capture events, you can select the standard ChangeEvents channel instead of creating a custom channel."). For the maximum number of channels that you can create for change events, see [Default Change Event Allocations](https://developer.salesforce.com/docs/atlas.en-us.change_data_capture.meta/change_data_capture/cdc_allocations_default_allocations.htm) in the Change Data Capture Developer Guide. ## The Standard `ChangeEvents` Channel The predefined standard channel `ChangeEvents` includes all change events that correspond to the Salesforce objects that you select in Setup. You can select `ChangeEvents` from the channel’s dropdown in the event relay creation wizard. Before you can use the standard `ChangeEvents` channel, from Setup, select the objects that you want change events for in the Change Data Capture page. For more information, see [Select Objects for Change Notifications in the User Interface](https://developer.salesforce.com/docs/atlas.en-us.change_data_capture.meta/change_data_capture/cdc_select_objects.htm) in the Change Data Capture Developer Guide. ## Filtered Channels for Platform Events and Change Events Add a filter to a custom channel and send only events that match the filter criteria to Amazon EventBridge. By using a filtered channel, you reduce the volume of events relayed to Amazon EventBridge, process events efficiently, and decrease the consumption of the event delivery allocation. Event relay filtering is available for custom channels that reference custom platform events and change events but not for real-time event monitoring events. To add a filter to a platform event channel, see [Filter Your Stream of Platform Events with Custom Channels](https://developer.salesforce.com/docs/atlas.en-us.platform_events.meta/platform_events/platform_events_filter_section.htm) in the Platform Events Developer Guide. To add a filter to a change data capture channel, see [Filter Your Stream of Change Events with Channels](https://developer.salesforce.com/docs/atlas.en-us.change_data_capture.meta/change_data_capture/cdc_filter_section.htm) in the Change Data Capture Developer Guide. ## Change Event Enrichment in Channels Change event messages include values for new and changed fields, but sometimes unchanged field values are needed for processing or replicating data. To enrich change events with one or more fields that are always present in the event message, create a custom channel with enriched fields. To learn how to add enrichment, see [Enrich Change Events with Extra Fields](https://developer.salesforce.com/docs/atlas.en-us.change_data_capture.meta/change_data_capture/cdc_enrich_intro.htm) in the Change Data Capture Developer Guide.