curl --request POST \
  --url https://api.iotools.cloud/v1/tool/css-specificity-calculator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "selectors": "#header"
}
'

{
  "tool": "css-specificity-calculator",
  "tool_version": "1.0.1",
  "outputs": {
    "results": [
      {
        "selector": "#header",
        "id": "1",
        "class": "0",
        "type": "0",
        "specificity": "(1, 0, 0)"
      }
    ]
  },
  "credits_used": 3,
  "credits_remaining": null
}