Event API webhook payload missing required fields for attendee registration automation

CRM Adobe Experience Cloud
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1

We’ve set up an automation workflow to register attendees through the Event Management API using webhooks. The webhook triggers successfully when a user submits the registration form, but our downstream automation is failing because critical fields are missing from the payload.

The webhook payload mapping seems incomplete - we’re receiving basic contact info but missing custom registration fields we defined in the event schema. Our workflow depends on these fields to assign attendees to the correct session tracks and send personalized confirmation emails.

Here’s what we’re receiving:

{
  "eventId": "evt_2024_summit",
  "attendeeEmail": "user@example.com",
  "registrationDate": "2025-03-14T09:15:00Z"
}

We extended the event schema to include sessionPreference, dietaryRestrictions, and accessibilityNeeds, but none of these appear in the webhook payload. The automation workflow errors out trying to process missing data. Has anyone successfully configured webhook payload mapping to include custom schema fields in AEC 2021?

2

I’ve seen this exact issue. The default webhook configuration in AEC 2021 only includes base event fields. You need to explicitly map your custom schema extensions in the webhook settings. Check the Event API documentation section on payload customization - there’s a configuration endpoint specifically for this.

3

One thing to watch out for - if your automation workflow is already running when you update the webhook configuration, you might need to restart it. The workflow engine caches the expected payload structure. Also verify that your custom fields are marked as ‘webhook-enabled’ in the schema definition. There’s a checkbox for this that’s easy to miss.

4

The webhook payload mapping is separate from schema definition. When you extend the event schema with custom fields, they don’t automatically flow through to webhooks. You need to update the webhook configuration to include those field mappings. In the Event Management module, go to Integration Settings > Webhooks > Payload Configuration. There should be an option to add custom field mappings. Map each of your extended fields (sessionPreference, dietaryRestrictions, accessibilityNeeds) to their corresponding schema attributes. This tells the webhook handler which fields to include in the outbound payload.

5

For the specific workflow failure you’re experiencing, here’s the complete solution addressing webhook payload mapping, schema extension integration, and automation workflow configuration.

First, verify your custom fields are properly configured for webhook delivery. In Event Management, navigate to Schema Extensions and confirm each custom field has the ‘Include in API Responses’ flag enabled:


Field: sessionPreference
  - Type: String
  - Include in API Responses: ✓ ENABLED
  - Webhook Enabled: ✓ ENABLED

Next, update your webhook payload mapping. Access Integration Hub > Event Webhooks > [Your Webhook] > Payload Configuration. Add explicit field mappings:

{
  "payloadMapping": {
    "eventId": "event.id",
    "attendeeEmail": "attendee.email",
    "registrationDate": "registration.timestamp",
    "sessionPreference": "registration.custom.sessionPreference",
    "dietaryRestrictions": "registration.custom.dietaryRestrictions",
    "accessibilityNeeds": "registration.custom.accessibilityNeeds"
  }
}

The key is mapping custom fields using the ‘registration.custom.’ prefix - this tells the webhook handler to pull from extended schema attributes rather than base fields.

For your automation workflow, update the trigger configuration to expect the expanded payload structure. In the workflow definition, add field validations:

  1. Modify workflow trigger to accept custom fields
  2. Add conditional logic to handle optional fields (some attendees may not provide dietary restrictions)
  3. Update downstream actions (email templates, session assignment logic) to reference the new payload structure

After updating webhook configuration, test with a sample registration. The payload should now include:

{
  "eventId": "evt_2024_summit",
  "attendeeEmail": "user@example.com",
  "registrationDate": "2025-03-14T09:15:00Z",
  "sessionPreference": "technical-track",
  "dietaryRestrictions": "vegetarian",
  "accessibilityNeeds": "wheelchair-access"
}

If fields still don’t appear after configuration updates, clear the webhook cache (Integration Hub > System > Clear Integration Cache) and restart your automation workflow. In AEC 2021, the webhook handler caches payload definitions for performance, so configuration changes require a cache refresh to take effect.

One final consideration: if you’re using API versioning, ensure your webhook is configured to use the correct API version that supports schema extensions. AEC 2021 requires API version 2.1 or higher for custom field support in webhooks.

6

We had similar workflow failures last quarter. Beyond the payload mapping, make sure your webhook endpoint can handle the extended payload size. When we added five custom fields, our receiving endpoint started timing out because the payload exceeded its buffer limit. Had to adjust both the AEC webhook configuration and our receiving service. Also recommend adding null checks in your automation workflow for the custom fields - sometimes they’re included in the payload but empty if the attendee skipped optional fields during registration.