Validate US ABA routing transit numbers with the 3-7-1 weighted checksum algorithm. Returns Federal Reserve district identification, bank lookup, and error details.
curl "https://bankcheck.dev/api/v1/validate?q=021000021"{
"apiVersion": "1",
"processingTimeMs": 1,
"result": {
"valid": true,
"format": "us-routing",
"normalized": "021000021",
"errors": [],
"breakdown": {
"formatName": "US Routing Number",
"parts": [
{ "label": "Fed District", "value": "02", "start": 0, "end": 2 },
{ "label": "Fed Office", "value": "1", "start": 2, "end": 3 },
{ "label": "Institution ID", "value": "00002", "start": 3, "end": 8 },
{ "label": "Check Digit", "value": "1", "start": 8, "end": 9 }
]
},
"bankInfo": {
"bankName": "JPMorgan Chase",
"bic": null,
"country": "United States",
"countryCode": "US",
"city": "Tampa"
}
}
}curl "https://bankcheck.dev/api/v1/validate?q=021000020"{
"apiVersion": "1",
"processingTimeMs": 0,
"result": {
"valid": false,
"format": "us-routing",
"normalized": "021000020",
"errors": [
{
"code": "CHECKSUM_FAILED",
"message": "Routing number checksum is incorrect",
"suggestion": "Verify the 9-digit number — the last digit is a check digit"
}
],
"breakdown": null,
"bankInfo": null
}
}| Field | Type | Description |
|---|---|---|
| Fed District | string | Federal Reserve district (01-12), e.g. 02 = New York |
| Fed Office | string | Federal Reserve office or processing center |
| Institution ID | string | 5-digit identifier for the specific bank |
| Check Digit | string | Single check digit computed via 3-7-1 weighted checksum |
| Field | Type | Description |
|---|---|---|
| NOT_NUMERIC | error | Input contains non-numeric characters |
| WRONG_LENGTH | error | Input is not exactly 9 digits |
| CHECKSUM_FAILED | error | The 3-7-1 weighted checksum verification failed |
The API looks up the bank name, city, and state for known routing numbers. The database covers 61 US banks with 150 routing numbers including JPMorgan Chase, Bank of America, Wells Fargo, Citibank, and more. See the routing number validator to browse all banks.
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