curl --request POST \
  --url https://api.iotools.cloud/v1/tool/fibonacci-retracement-calculator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "swingHigh": "150",
  "swingLow": "100",
  "trend": "up",
  "decimals": "2"
}
'

{
  "tool": "fibonacci-retracement-calculator",
  "tool_version": "1.0.1",
  "outputs": {
    "summary": "Uptrend · Range 50.00 (High 150.00 - Low 100.00). Key 61.8% level at 119.10.",
    "retracement": [
      {
        "level": "0%",
        "price": "150.00",
        "notes": "Swing high"
      },
      {
        "level": "23.6%",
        "price": "138.20",
        "notes": "Shallow"
      },
      {
        "level": "38.2%",
        "price": "130.90",
        "notes": "Common pullback"
      },
      {
        "level": "50%",
        "price": "125.00",
        "notes": "Halfway (psychological)"
      },
      {
        "level": "61.8%",
        "price": "119.10",
        "notes": "Golden ratio"
      },
      {
        "level": "78.6%",
        "price": "110.70",
        "notes": "Deep pullback"
      },
      {
        "level": "100%",
        "price": "100.00",
        "notes": "Swing low"
      }
    ],
    "extension": [
      {
        "level": "127.2%",
        "price": "163.60",
        "notes": "Target 1"
      },
      {
        "level": "161.8%",
        "price": "180.90",
        "notes": "Golden extension"
      },
      {
        "level": "200%",
        "price": "200.00",
        "notes": "Target 2"
      },
      {
        "level": "261.8%",
        "price": "230.90",
        "notes": "Extended target"
      }
    ]
  },
  "credits_used": 3,
  "credits_remaining": null
}