# Custom Fields

### Custom fields

Storage items support **custom fields** defined in your system (e.g. in `custom_fields`). You can set them when creating or updating a storage item and they are returned in list/get responses.

Request body (create/update): use the optional `custom_fields` array. Each entry has:

| Property   | Type                                 | Description                                                                                       |
| ---------- | ------------------------------------ | ------------------------------------------------------------------------------------------------- |
| `field_id` | number                               | ID of the custom field (positive integer).                                                        |
| `value`    | string \| number \| array of strings | Field value. Strings max 255 characters. Use an array for multi-value fields (e.g. multi-select). |

Response: custom data is returned in the `custom_fields` array on each storage object. Each element includes metadata (e.g. `field_id`, `field_name`, `type_id`, `editor_type`, `enabled`, `sort_value`) and the stored `value`. Dynamic keys of the form `custom_field_{field_id}` also expose the value for convenience.

Create example with custom fields

```http
POST /storage
Content-Type: application/json

{
  "type": "HDD",
  "make": "Vendor",
  "model_name": "Model X",
  "capacity": 1000,
  "capacity_unit": "GB",
  "location_id": 1,
  "custom_fields": [
    { "field_id": 1, "value": "Evidence" },
    { "field_id": 2, "value": 42 },
    { "field_id": 3, "value": ["TagA", "TagB"] }
  ]
}
```

Update example: set or replace custom fields

Include `custom_fields` in the PATCH body. For each `field_id`, the value is set or replaced. To clear a custom value, send an empty value (`""`, `null`, or `[]` for array-type fields).

```http
PATCH /storage/550e8400-e29b-41d4-a716-446655440000
Content-Type: application/json

{
  "custom_fields": [
    { "field_id": 1, "value": "Updated label" },
    { "field_id": 2, "value": "" }
  ]
}
```

Response example (excerpt): `custom_fields` in a GET or create/update response may look like:

```json
"custom_fields": [
  {
    "attribute_id": 101,
    "item_id": 1,
    "field_id": 1,
    "field_name": "Category",
    "value": "Evidence",
    "type_id": 1,
    "editor_type": "text",
    "enabled": 1,
    "sort_value": 0,
    "custom_field_1": "Evidence"
  }
]
```