---
title: "Custom field definitions"
description: "Custom field definitions: available fields, filters, associations, and API operations."
lastModified: "2026-08-21"
---

**Path:** `events/{event_id}/custom-field-definitions`  
**Methods:** GET collection/record, POST, PATCH. There is no DELETE operation.

**GET**

- Fields: `event-id`, `key`, `title`, `customizable-type`, `visible-to-sponsors`, `filterable`, `role`, `field-type`, `options`, `position`, `visible-on-registrant-profile`, `required`, `created-at`, `updated-at`, `is-onboarding-question`.  
- Filters: `customizable_type`, `role`, `visible_to_sponsors`, `filterable`.  
- Association: `onboarding_step_questions` → response `onboarding-questions`, with `onboarding-step-id`, `title`, `description`, `position`, `required`.

```
GET .../custom-field-definitions?customizable_type=Event%3A%3ARegistrant&include=onboarding_step_questions
```

**POST/PATCH inputs:** `key`, `title`, `customizable_type`, `visible_to_sponsors`, `filterable`, `field_type`, `options` (array), and `visible_on_registrant_profile`.

```json
{
  "key": "linkedin_url",
  "title": "LinkedIn URL",
  "customizable_type": "Event::Registrant",
  "field_type": "Text",
  "options": [],
  "visible_to_sponsors": true
}
```

`Event::Invite` is normalized to `Event::Registrant` on create. Unsupported customizable types and duplicate keys are rejected. `key` and `customizable_type` cannot be changed through PATCH; attempts are ignored. The request parameter `visible_on_registrant_profile` maps to the underlying writable field exposed in introspection as `visible_on_attendee_profile`.

Despite its name, `is-onboarding-question` is the count of onboarding-step question rows for the definition, normally `0` or `1`, rather than a JSON boolean.