curl --request POST \
  --url https://api.iotools.cloud/v1/tool/euler-characteristic-calculator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "vertices": "8",
  "edges": "12",
  "faces": "6"
}
'

{
  "tool": "euler-characteristic-calculator",
  "tool_version": "1.0.2",
  "outputs": {
    "results": [
      {
        "metric": "Vertices (V)",
        "value": "8"
      },
      {
        "metric": "Edges (E)",
        "value": "12"
      },
      {
        "metric": "Faces (F)",
        "value": "6"
      },
      {
        "metric": "Euler characteristic (χ)",
        "value": "2"
      }
    ],
    "classification": [
      {
        "property": "Orientable genus (g)",
        "value": "0"
      },
      {
        "property": "Nonorientable crosscap number (k)",
        "value": "N/A"
      },
      {
        "property": "Possible named surfaces",
        "value": "Sphere (closed, orientable, genus 0)"
      }
    ]
  },
  "credits_used": 5,
  "credits_remaining": null
}