ABA Routing Number

GET/v0/aba

Validates a 9-digit ABA routing transit number (RTN) used by U.S. financial institutions for ACH transfers, wire transfers, and direct deposits. Verifies the check digit using the standard weighted-sum algorithm and extracts the Federal Reserve district encoded in the routing symbol. Spaces and hyphens in the input are stripped automatically.

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Query Parameters

Parameter	Type	Required	Description
value	string	Yes	The 9-digit ABA routing number to validate

Example Request

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/aba?value=102101645"

Response Fields

Field	Type	Description
valid	boolean	Whether the routing number passes the ABA check digit algorithm
routingNumber	string	The normalized 9-digit routing number (spaces and hyphens removed)
federalReservePrefix	string	First two digits — the Federal Reserve routing symbol
federalReserveDistrict	string	Name of the Federal Reserve district (e.g. `Denver`, `San Francisco`). Omitted when the prefix is not a known district code.
abaInstitutionIdentifier	string	Digits 3–8 — the ABA institution identifier assigned to the bank
checkDigit	number	The 9th digit used as the check digit

Example Response

{
  "valid": true,
  "routingNumber": "102101645",
  "federalReservePrefix": "10",
  "federalReserveDistrict": "Kansas City",
  "abaInstitutionIdentifier": "210164",
  "checkDigit": 5
}