Magento2 REST API - POST configurable product options : What is the value_index field?

Question

I have to create a configurable product, then simple products to finally link them together. I followed the steps of the documentation, ie post the configurable, then post the simple products.

The next step defined in the doc is to set the configuration attribute: https://devdocs.magento.com/guides/v2.4/rest/tutorials/configurable-product/define-config-product-options.html

On this example given by the documentation, I understand that it is necessary to give the id of the attribute, its label (which I find useless moreover since the attribute already exists), its position (I do not understand this fields either).

What I don't understand at all is the "values" array and in particular its content: "value_index".

{
  "option": {
    "attribute_id": "141",
    "label": "Size",
    "position": 0,
    "is_use_default": true,
    "values": [
      {
        "value_index": 9
      }
    ]
  }
}

The documentation says "The value assigned to the value_index must be unique within the system." but it does not explain its meaning or its usefulness. I don't know what to give as a value. Can you explain the meaning of this value to me?

Answer 1

"Value_index" is the configurable attribute option Id, which you want to use for this product. Simply it is configurable attribute's option id.