curl --request POST \
  --url https://api.iotools.cloud/v1/tool/sales-tax-vat-calculator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "mode": "add",
  "price": "100",
  "ratePreset": "custom",
  "taxRate": "20"
}
'

{
  "tool": "sales-tax-vat-calculator",
  "tool_version": "1.0.1",
  "outputs": {
    "result": [
      {
        "metric": "Total (incl. Tax)",
        "value": "120.00"
      },
      {
        "metric": "Pre-Tax Price",
        "value": "100.00"
      },
      {
        "metric": "Tax Amount",
        "value": "20.00"
      },
      {
        "metric": "Tax Rate",
        "value": "20%"
      }
    ]
  },
  "credits_used": 3,
  "credits_remaining": null
}