curl --request POST \
  --url https://api.iotools.cloud/v1/tool/routing-number-validator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "routingNumber": "021000021"
}
'

{
  "tool": "routing-number-validator",
  "tool_version": "1.0.1",
  "outputs": {
    "result": [
      {
        "property": "Status",
        "value": "Valid ABA routing number"
      },
      {
        "property": "Valid",
        "value": "Yes"
      },
      {
        "property": "Federal Reserve District",
        "value": "02 — Federal Reserve Bank of New York"
      },
      {
        "property": "Check Digit",
        "value": "1"
      }
    ],
    "steps": "ABA checksum for: 021000021\n\nPos  Digit  Weight  Product\n---  -----  ------  -------\n  1      0       3        0\n  2      2       7       14\n  3      1       1        1\n  4      0       3        0\n  5      0       7        0\n  6      0       1        0\n  7      0       3        0\n  8      2       7       14\n  9      1       1        1\n\nSum = 30\n30 mod 10 = 0\n\nValid — the weighted sum is divisible by 10."
  },
  "credits_used": 3,
  "credits_remaining": null
}