> ## Documentation Index
> Fetch the complete documentation index at: https://help.hoopai.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Association Update | Webhook Events

> Fires when an existing association type definition is modified.

The `AssociationUpdate` event fires whenever an existing association type definition is modified in an account. Changes can include updating labels, adjusting cardinality, or modifying other relationship metadata. Supports contact-to-contact, contact-to-custom object, and custom object-to-custom object relationship types. Use this event to detect model changes and re-validate downstream integrations that depend on this association structure.

## Payload

| Field               | Type     | Description                                                                       |
| ------------------- | -------- | --------------------------------------------------------------------------------- |
| `id`                | `string` | Unique identifier for the association definition                                  |
| `key`               | `string` | Unique key for this association type (e.g., `"custom_objects.buyer_to_property"`) |
| `firstObjectKey`    | `string` | Object type key for the first side of the association                             |
| `secondObjectKey`   | `string` | Object type key for the second side of the association                            |
| `firstObjectLabel`  | `string` | Human-readable label for the first object's role in the relationship              |
| `secondObjectLabel` | `string` | Human-readable label for the second object's role in the relationship             |
| `associationType`   | `string` | Whether the association is `"USER_DEFINED"` or system-defined                     |
| `cardinality`       | `string` | Relationship cardinality, e.g. `"MANY_TO_MANY"`                                   |
| `locationId`        | `string` | Account ID where the association type was updated                                 |

## Example payload

```json theme={null}
{
  "id": "67ade73d1119d2ac7ad0c475",
  "key": "custom_objects.buyer_to_property",
  "firstObjectKey": "custom_objects.buyer",
  "secondObjectKey": "custom_objects.property",
  "firstObjectLabel": "Interested Buyer",
  "secondObjectLabel": "Property",
  "associationType": "USER_DEFINED",
  "cardinality": "MANY_TO_MANY",
  "locationId": "eHy2cOSZxMQzQ6Yyvl8P"
}
```

## Related

* [Association Create](/api-reference/webhooks/association-create) — fires when a new association type is defined
* [Associations API](/api-reference/associations/overview) — manage association definitions and relations