curl --request POST \
  --url https://api.iotools.cloud/v1/tool/api-signature-generator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "message": "message",
  "secretKey": "key",
  "outputFormat": "hex"
}
'

{
  "tool": "api-signature-generator",
  "tool_version": "1.0.1",
  "outputs": {
    "signature": "6e9ef29b75fffc5b7abae527d58fdadb2fe42e7219011976917343065f58ed4a"
  },
  "credits_used": 3,
  "credits_remaining": null
}