Skip to content
HubSpot Developer Changelog

New Size Limits for App Events and App Event Properties

We have revised the size restrictions for App Events, also referred to as Timeline Events or Integration Events, to ensure seamless integration within the UnifiedEvents ecosystem.

What's changing?

Previously, the instance size limitations were:

  • Event Instance ID: No limit
  • Per Property/Token: 512 KB
  • Total Instance Size: 2 MB, including all properties and token names

New Size Restrictions:

  • Event Instance ID: 500 bytes
  • Per Property/Token: Reduced to 510 KB (from 512 KB)
  • Total Instance Size: Reduced to 1 MB, including all properties and the instance ID

Users can generate and send event instances from their integrator applications into their portal. These instances must be authenticated and validated against the new size limits before submission, or they will be rejected with an error. See the example below of the expected error response: 

// Example response { "status": 400, "errors": [ { "message": "Event {id} failed with validation error(s)" } ] }

These new limits improve integration processes and data management within UnifiedEvents environments, maintaining data integrity and functionality. 

When is it happening?

This went into effect on Monday, March 17th, 2025.  


Questions or comments? Join us in the developer forums for a peer-to-peer discussion.