curl --request POST \
  --url https://api.iotools.cloud/v1/tool/molar-mass-calculator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "formula": "H2O",
  "unit": "g/mol",
  "precision": "4"
}
'

{
  "tool": "molar-mass-calculator",
  "tool_version": "1.0.1",
  "outputs": {
    "molarMass": "18.0150 g/mol",
    "breakdown": [
      {
        "element": "O",
        "count": "1",
        "atomic-mass": "15.999",
        "subtotal": "15.999"
      },
      {
        "element": "H",
        "count": "2",
        "atomic-mass": "1.008",
        "subtotal": "2.016"
      }
    ]
  },
  "credits_used": 3,
  "credits_remaining": null
}