Get a custom field definition
Platform module
GET/custom-field-definitions/{id}customFieldDefinitions.get
A custom field on a built-in resource. Returns one custom field definition with its `ETag`. A custom field definition the caller may not see returns 404.
- Requires the capability org.settings.read.
- OAuth scopes: org.
- Error statuses: 400, 401, 404, 429. Errors are RFC 9457 problem details.
Path and query parameters
| Field | Type | Required | Description |
|---|---|---|---|
| id | string (uuid) | Yes | Identifier of the custom field definition. |
| fields | Fields | No | Sparse fieldset: a comma-separated list of top-level fields to return. `id` is always returned.Constraints: pattern ^[a-z_][a-z0-9_]*(,[a-z_][a-z0-9_]*)*$ |
Response 200: CustomFieldDefinition
| Field | Type | Required | Description |
|---|---|---|---|
| id | string (uuid) | Yes | Identifier of the custom field definition. |
| org_id | string (uuid) | Yes | Identifier of the owning organization, derived from the parent row and never accepted from the caller. |
| created_at | string (date-time) | Yes | When the row was created. |
| created_by | string (uuid) | null | Yes | Identifier of the person who created the row; null when a seed, platform or system process created it. |
| updated_at | string (date-time) | Yes | When the row was last updated. |
| updated_by | string (uuid) | null | Yes | Identifier of the person who last updated the row; null when a seed, platform or system process updated it. |
| target_table | string | Yes | Table the field extends.Constraints: pattern ^[A-Za-z0-9][A-Za-z0-9._-]{0,63}$ |
| field_key | string | Yes | Field key.Constraints: pattern ^[A-Za-z0-9][A-Za-z0-9._-]{0,63}$ |
| label | string | Yes | Label.Constraints: length 1 to 300 |
| data_type | string | Yes | Data type.Constraints: pattern ^[A-Za-z0-9][A-Za-z0-9._-]{0,63}$ |
| required | boolean | Yes | True when forms require a value. |
| filterable | boolean | Yes | True when views filter on the field; it adds a partial index. |
| sort_order | integer | Yes | Position in forms.Constraints: range 0 to any |
{
"id": "0192f1e2-7c3a-7b4d-9e8f-1a2b3c4d5e6f",
"org_id": "0192f1e2-7c3a-7b4d-9e8f-1a2b3c4d5e6f",
"created_at": "2026-10-08T14:30:00Z",
"created_by": "0192f1e2-7c3a-7b4d-9e8f-1a2b3c4d5e6f",
"updated_at": "2026-10-08T14:30:00Z",
"updated_by": "0192f1e2-7c3a-7b4d-9e8f-1a2b3c4d5e6f",
"target_table": "app.vendors",
"field_key": "union_signatory",
"label": "Union Signatory",
"data_type": "boolean",
"required": false,
"filterable": false,
"sort_order": 1
}Code samples
curl -X GET "$XOS_BASE_URL/custom-field-definitions/0192f1e2-7c3a-7b4d-9e8f-1a2b3c4d5e6f" \
-H "Authorization: Bearer $XOS_API_KEY"const { data, etag } = await xos.customFieldDefinitions.get("0192f1e2-7c3a-7b4d-9e8f-1a2b3c4d5e6f");response = xos.custom_field_definitions.get("0192f1e2-7c3a-7b4d-9e8f-1a2b3c4d5e6f")xos custom-field-definitions get 0192f1e2-7c3a-7b4d-9e8f-1a2b3c4d5e6f