curl --request POST \
  --url https://api.iotools.cloud/v1/tool/invisible-character-generator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "charType": "zwsp",
  "count": "3"
}
'

{
  "tool": "invisible-character-generator",
  "tool_version": "1.0.1",
  "outputs": {
    "output": "​​​",
    "preview": "\\u200B\\u200B\\u200B",
    "info": "Zero-Width Space · U+200B · 3 characters"
  },
  "credits_used": 3,
  "credits_remaining": null
}