Add product with text customisable option to cart using REST

Question

When using the REST API to add products to the cart, you need to add a product_option.extension_attributes.configurable_item_options object to the cartItem payload (POST-ing to /V1/carts/mine/items). So far I got this working for simple products. Now I need to add products that have customizable options that are text fields, I tried sending that as following:

// product_option.extension_attributes.configurable_item_options
{
    "option_id": "16",
    "option_value": "Some text"
}

This returns the following error message: "Error occurred during \"product_option\" processing. Error occurred during \"extension_attributes\" processing. Error occurred during \"configurable_item_options\" processing. Error occurred during \"option_value\" processing. The \"Some text\" value's type is invalid. The \"int\" type was expected. Verify and try again."

If I change "Some text" to 0 it complains not all required options are set, and obviously I'm not passing my content anymore.

For reference; this is the actual option_id information retrieved from rest/V1/products/XX/options

{
    "product_sku": "XX",
    "option_id": 16,
    "title": "Text 1st line",
    "type": "field",
    "sort_order": 7,
    "is_require": true,
    "price": 0,
    "price_type": "fixed",
    "sku": "TEXT-ONE",
    "max_characters": 0,
    "image_size_x": 0,
    "image_size_y": 0
},

Also the full payload of the add-item request:

{
  "cartItem": {
    "sku": "HG-03",
    "qty": 1,
    "quote_id": "80",
    "product_option": {
      "extension_attributes": {
        "configurable_item_options": [
          {
            "option_id": "16",
            "option_value": "Some text"
          }
        ]
      }
    }
  }
}

So to sum it up: How to properly send the value for customisable text fields on products using the REST API in Magento 2.3?

Answer 1

Your payload should be something like this:

{
  "cartItem": {
    "sku": "HG-03",
    "qty": 1,
    "quote_id": "80",
    "product_option": {
      "extension_attributes": {
        "custom_options": [
          {
            "option_id": "16",
            "option_value": "Some text"
          }
        ]
      }
    }
  }
}

You are adding custom options, not configurable items options.