Platform Events Developer Guide

Platform Events Developer Guide
Delivering Custom Notifications with Platform Events
Defining Your Custom Platform Event
Publishing Platform Events
Subscribing to Platform Events
Testing Your Platform Event in Apex
Encrypting Platform Event Messages at Rest in the Event Bus
Considerations
Examples
Reference
Platform Event Allocations
EventBusSubscriber
EventBus Class
Platform Event Error Status Codes
TriggerContext Class
Standard Platform Event Objects
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Platform Event Allocations

Learn about the allocations available for platform event definitions, publishing and subscribing to platform events, and event delivery in CometD clients.

Common Platform Event Allocations

The following allocations apply to standard-volume and high-volume platform events.

Description Performance and Unlimited Editions Enterprise Edition Developer Edition Professional Edition (with API Add-On)
Maximum number of platform event definitions that can be created in an org 100 50 5 5
Maximum number of concurrent CometD clients (subscribers) across all channels and for all event types 2,000 1,000 20 20
Maximum number of processes that can subscribe to a platform event 4,000 4,000 4,000 5
Maximum number of active processes that can subscribe to a platform event 2,000 2,000 2,000 5
  • The concurrent client allocation is shared with all types of events that you can subscribe to through Streaming API (CometD), including PushTopic, generic, and platform events. The empApi Lightning component uses CometD and consumes the concurrent client allocation like any other CometD client. If multiple browser tabs use empApi, the streaming connection is shared and is counted as one client only. A client that exceeds the concurrent client allocation receives an error and can't subscribe. When one of the clients disconnects and a connection is available, the new client can subscribe. See Streaming API Error Codes in the Streaming API Developer Guide.
  • Platform events that originate from an installed managed package share the org’s allocation for the maximum number of platform event definitions.

Note

High-Volume Platform Event Default Allocations

If your org has no add-on licenses, default allocations apply and can't be exceeded. Each Salesforce edition provides a default allocation for the number of events delivered to CometD clients. The default allocation is enforced daily to ensure fair sharing of resources in the multitenant environment and to protect the service. Default allocations are not part of the usage-based entitlement.

The number of delivered events to external CometD clients is counted per subscribed client. If you have multiple client subscribers, your usage is added across all subscribers. For example, you have an Unlimited Edition org with a default allocation of 50,000 events in a 24-hour period. Within a few hours, 20,000 event messages are delivered to two subscribed clients. You have consumed 40,000 events, and you are still entitled to 10,000 events within the 24-hour period.

If you exceed the default event delivery allocation, you receive an error. See Streaming API Error Codes in the Streaming API Developer Guide. Event messages that are generated after exceeding the allocation are stored in the event bus. You can retrieve stored event messages as long as they are within the retention window of 72 hours.

Table 1. Default Allocations
Description Performance and Unlimited Editions Enterprise Edition and Professional Edition (with API Add-On) Developer Edition
Event Delivery: maximum number of delivered event notifications within a 24-hour period, shared by all CometD clients 50,000 25,000 10,000
Event Publishing: maximum number of event notifications published per hour 250,000 250,000 50,000

High-Volume Platform Event Add-On License and Usage-Based Entitlements

The add-on increases the 24-hour allocation of delivered event notifications by 100,000 per day (3 million a month) as a usage-based entitlement. The entitlement gives you flexibility in how you use your allocations. The entitlement is not as strictly enforced as the default allocation. With the entitlement, you can exceed your 24-hour event delivery allocation by a certain amount.

Salesforce monitors event overages based on a calendar month, starting with your contract start date. If you exceed the monthly entitlement, Salesforce contacts you to discuss your event usage needs. The entitlement used for monitoring monthly event overages is the daily allocation multiplied by 30.

When you purchase an add-on license, the hourly event publishing allocation is increased by 25,000 events per hour.

Table 2. Example: Entitlement with One High-Volume Platform Event Add-On License
Description Performance and Unlimited Editions Enterprise Edition and Professional Edition (with API Add-On)
Event Delivery: entitlement for delivered event notifications within a 24-hour period, shared by all CometD clients

You can exceed this entitlement by a certain amount before receiving an error. Salesforce uses the monthly entitlement for event overage monitoring. The monthly entitlement is returned in the limits REST API resource.

 150,000 (50K included with org license + 100K from add-on license)

Monthly entitlement: 4.5 million (1.5 million included with org license + 3 million from add-on license)

 125,000 (25K included with org license + 100K from add-on license)

Monthly entitlement: 3.75 million (0.75 million included with org license + 3 million from add-on license)
Event Publishing: maximum number of event notifications published per hour 275,000 (250K included with org license + 25K from add-on license) 275,000 (250K included with org license + 25K from add-on license)

The maximum event message size that you can publish is 1 MB. If your event object has hundreds of custom fields or many long text area fields, you could hit this limit. In this case, the publishing call gets an error.

  • The default allocations and usage-based entitlement of delivered events are shared between high-volume platform events and Change Data Capture events.
  • Non-CometD clients, including Apex triggers, processes, and flows, don’t count against the event delivery limit. The number of event messages that an Apex trigger, process, or flow can process depends on how long the processing takes for each subscriber. The longer the processing time, the longer it takes for the subscriber to reach the tip of the event stream.
  • The empApi Lightning component is a CometD client. As a result, the event delivery allocation applies to the component and it is per channel per unique browser session.

Note

Monitor Your High-Volume Event Usage

To monitor your monthly high-volume event delivery usage, use the limits REST API resource, and inspect the MonthlyPlatformEventsUsageEntitlement value. The MonthlyPlatformEventsUsageEntitlement limits resource value returns the monthly entitlement or default allocation and your remaining allocation. If you don’t have an add-on license, your daily default maximum allocation is the monthly value returned divided by 30. For more information, see List Organization Limits in the REST API Developer Guide. If you have an add-on license, you can view your platform event monthly entitlement in Setup, on the Company Information page, under Usage-based Entitlements.

Standard-Volume Platform Event Allocations

The following allocations are for standard-volume events defined in API version 44.0 and earlier.

You can no longer define new standard-volume platform events. New platform events are high volume by default.

Note

Description Performance and Unlimited Editions Enterprise Edition Developer Edition and Professional Edition (with API Add-On)
Event Delivery: maximum number of delivered event notifications within a 24-hour period, shared by all CometD clients1 50,000 25,000 10,000
Event Publishing: maximum number of event notifications published per hour 100,000 100,000 1,000

If you exceed the event delivery allocation, you receive an error. See Streaming API Error Codes in the Streaming API Developer Guide. Event messages that are generated after exceeding the allocation are stored in the event bus. You can retrieve stored event messages as long as they are within the retention window of 24 hours.

To monitor your standard-volume event delivery usage, use the limits REST API resource and inspect the DailyStandardVolumePlatformEvents value. For more information, see List Organization Limits in the REST API Developer Guide.

1To request a higher number of events delivered to CometD clients, contact Salesforce to purchase an add-on license. The add-on license increases your daily limit of delivered events by 100,000 more events. For example, for Unlimited Edition, the add-on license increases the daily limit of delivered events from 50,000 to 150,000 events. You can purchase multiple add-ons to meet your event requirements for CometD clients. To avoid deployment problems and degradation in service, we recommend that the number of events delivered to CometD clients not exceed 5 million per day. If you require more external events, contact your Salesforce representative to understand how the product can scale to meet your needs.