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

# Add Shipping Method

> Add a seller shipping option to the cart.

Adds the chosen shipping option to the cart through Mercur's seller-aware workflow, so each seller's items can carry their own shipping method.

## Path parameters

<ParamField path="id" type="string" required>
  The cart's ID.
</ParamField>

## Query parameters

<ParamField query="fields" type="string">
  Comma-separated fields and relations to include on the returned cart; prefix with `+`/`-` to add to or remove from the defaults.
</ParamField>

## Body parameters

<ParamField body="option_id" type="string" required>
  ID of the shipping option to add.
</ParamField>

<ParamField body="data" type="object">
  Provider-specific data forwarded to the fulfillment provider.
</ParamField>

<ParamField body="additional_data" type="object">
  Data passed to the workflow's hooks.
</ParamField>

## Response

<ResponseField name="cart" type="object">
  <Expandable title="properties">
    <ResponseField name="id" type="string">The cart's ID.</ResponseField>
    <ResponseField name="currency_code" type="string">The cart's currency.</ResponseField>
    <ResponseField name="items" type="object[]">Line items in the cart.</ResponseField>
    <ResponseField name="shipping_methods" type="object[]">Shipping methods with `shipping_option_id`, `amount`, and tax lines.</ResponseField>
    <ResponseField name="shipping_total" type="number">Total shipping amount.</ResponseField>
    <ResponseField name="total" type="number">Cart total including tax and shipping.</ResponseField>
  </Expandable>
</ResponseField>

<RequestExample>
  ```bash cURL theme={null}
  curl -X POST 'http://localhost:9000/store/carts/cart_01JB2KB1CD/shipping-methods' \
    -H 'Content-Type: application/json' \
    -H 'x-publishable-api-key: pk_01JB2K3XYZ' \
    -d '{"option_id": "so_01JB2KC4GH"}'
  ```

  ```ts JS Client theme={null}
  const { cart } = await client.store.carts.$id.shippingMethods.mutate({
    $id: "cart_01JB2KB1CD",
    option_id: "so_01JB2KC4GH",
  })
  ```
</RequestExample>

<ResponseExample>
  ```json 200 theme={null}
  {
    "cart": {
      "id": "cart_01JB2KB1CD",
      "currency_code": "eur",
      "items": [{ "id": "cali_01JB2KB3EF", "quantity": 1, "unit_price": 4500 }],
      "shipping_methods": [
        {
          "shipping_option_id": "so_01JB2KC4GH",
          "amount": 900,
          "is_tax_inclusive": false,
          "tax_lines": []
        }
      ],
      "shipping_total": 900,
      "total": 5400
    }
  }
  ```
</ResponseExample>