## Update basket item

`PATCH /v1/basket-items/:id`

Updates the fields of an existing basket item. Pass only the fields you change, flat at the root of the JSON — no `fields` wrapper.

## Parameters

| Parameter | Type | Req. | Description |
|----------|-----|:-----:|---------|
| `id` (path) | number | yes | Item identifier |

## Fields to update (body)

| Parameter | Type | Description |
|----------|-----|---------|
| `quantity` | number | Quantity |
| `price` | number | Price per unit |
| `basePrice` | number | Base price before discount |
| `discountPrice` | number | Discount amount per unit |
| `currency` | string | Currency |
| `name` | string | Product name override |
| `vatRate` | number | VAT rate as a fraction of one |
| `vatIncluded` | boolean | Whether VAT is included in the price |
| `customPrice` | boolean | Protects the price from auto-recalculation |
| `weight` | number | Weight in grams |
| `measureCode` | number | Measurement unit code |
| `xmlId` | string | External identifier |

All item fields are editable except the service ones (`id`, `orderId`, `productId`, `productXmlId`, `catalogXmlId`, `dateInsert`, `dateUpdate`). The full set of available fields is visible in the response of [`GET /v1/basket-items/:id`](./get.md).

> **Partial update.** You do not need to pass `quantity` in every request. When `quantity` is absent from the body, the wrapper reads the item's current quantity and substitutes it — you can change only the price or another field. If the item is not found during such a partial update, `404 ENTITY_NOT_FOUND` is returned.

## Examples

### curl — personal key

```bash
curl -X PATCH "https://vibecode.bitrix24.com/v1/basket-items/9" \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "quantity": 3,
    "discountPrice": 50
  }'
```

### curl — OAuth app

```bash
curl -X PATCH "https://vibecode.bitrix24.com/v1/basket-items/9" \
  -H "X-Api-Key: YOUR_APP_KEY" \
  -H "Authorization: Bearer USER_SESSION_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "quantity": 3,
    "discountPrice": 50
  }'
```

### JavaScript — personal key

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/basket-items/9', {
  method: 'PATCH',
  headers: {
    'X-Api-Key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    quantity: 3,
    discountPrice: 50,
  }),
})

const { success, data } = await res.json()
```

### JavaScript — OAuth app

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/basket-items/9', {
  method: 'PATCH',
  headers: {
    'X-Api-Key': 'YOUR_APP_KEY',
    'Authorization': 'Bearer USER_SESSION_TOKEN',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    quantity: 3,
    discountPrice: 50,
  }),
})

const { success, data } = await res.json()
```

## Response fields

| Field | Type | Description |
|------|-----|---------|
| `data` | object | The updated item object with all fields |

## Response example

```json
{
  "success": true,
  "data": {
    "id": 9,
    "orderId": 33,
    "productId": 119,
    "name": "Home Slippers Favorite Sport",
    "price": 470,
    "basePrice": 470,
    "discountPrice": 50,
    "currency": "USD",
    "quantity": 3,
    "vatRate": 0,
    "vatIncluded": true,
    "customPrice": false,
    "canBuy": true,
    "weight": 0,
    "measureCode": 796,
    "measureName": "pcs",
    "dateUpdate": "2026-05-13T11:58:14.000Z"
  }
}
```

## Error response example

422 — item not found:

```json
{
  "success": false,
  "error": {
    "code": "BITRIX_ERROR",
    "message": "basket item is not exists"
  }
}
```

## Errors

| HTTP | Code | Description |
|------|-----|---------|
| 404 | `ENTITY_NOT_FOUND` | Item not found (partial PATCH without `quantity` — detected on pre-fetch) |
| 422 | `BITRIX_ERROR` | An item with this ID was not found (PATCH with explicit `quantity`) |
| 400 | `BITRIX_ERROR` | Invalid field value |
| 403 | `SCOPE_DENIED` | The API key lacks the `sale` scope |
| 401 | `TOKEN_MISSING` | The API key has no configured tokens |

For the full list of common API errors, see [Errors](/docs/errors).

## Known specifics

**The fields `id`, `orderId`, `productId`, `productXmlId`, `catalogXmlId`, `dateInsert` are read-only.** They are set on creation, and an attempt to change them is ignored. To move an item to another order, delete it via [`DELETE /v1/basket-items/:id`](./delete.md) and create a new one via [`POST /v1/basket-items`](./create.md).

**Price protection via `customPrice`.** With `customPrice: true`, the item price will not be recalculated automatically when the catalog product price changes.

## See also

- [Get item](./get.md)
- [List items](./list.md)
- [Delete item](./delete.md)
- [Batch](/docs/batch)
- [Limits and optimization](/docs/optimization)