Austrian bank code lookup — the OeNB directory

Austria calls it a Bankleitzahl too, but it is five digits, not Germany's eight: positions 5–9 of an AT IBAN. The register behind it is the Oesterreichische Nationalbank, SEPA-Zahlungsverkehrs-Verzeichnis — the OeNB's own directory of Austrian payment participants, and the allocation authority for those five digits.

It is also the richest reference set we hold. Where the German file stops at postcode and town, the OeNB publishes the full seat address of the institution — street and number included — and its LEI, which no other national register we consult carries.

One call

curl -X POST https://api.ibanforge.com/v1/iban/validate \
  -H "Content-Type: application/json" \
  -d '{"iban": "AT611904300234573201"}'

{
  "valid": true,
  "bic": null,
  "bank_code_check": {
    "value": "19043",
    "status": "not_in_register",
    "match": null,
    "register": "Oesterreichische Nationalbank SEPA-Zahlungsverkehrs-Verzeichnis",
    "authoritative": true,
    "as_of": "2026-08"
  }
}

That IBAN is not a typo. AT61 1904 3002 3457 3201 is Austria's official example IBAN, the one copied into tutorials, test suites and API documentation everywhere — and its bank code 19043 is allocated to nobody. The structure is perfect (valid: true), the allocation is empty (not_in_register), and both statements are true at once. We wrote up the pattern, across four countries' official examples, in the world's two favourite example IBANs point at bank codes that don't exist.

bic is null for the same reason: there is no allocated institution to name, and guessing one would be worse than an honest null.

What `not_in_register` means here

authoritative: true is the field that gives that "no" its weight. It says the reference set consulted is the register that hands out Austrian bank codes — so an absence is the allocation authority's own verdict, not a gap in our data. Everywhere we fall back to the composite BIC map, an absence proves nothing; here it does.

What the OeNB register publishes

For an allocated code, bank_code_check.institution carries what the directory holds:

Field	In the Austrian register	Note
`name`	yes	the institution as the OeNB lists it
`street`	yes	full street and number — the only register besides SIX's Swiss BankMaster that publishes one
`post_code` / `town`	yes	seat
`lei`	yes, where allocated	the Legal Entity Identifier, straight from the directory — served only when the register carries one

Absent fields stay null. Nothing here is enriched from a third source and passed off as the register's.

Freshness — and one honest asymmetry

The OeNB republishes its directory daily. We refresh it monthly, in the same cycle as the other national registers, and every answer stamps the edition it read in as_of (2026-08 above). So a code allocated in Vienna today can be up to a month away from answering verified here. We would rather say that plainly than describe the source's cadence as if it were ours.

The honest limits

We check the bank code, never the account or its holder. A verified Austrian code names the institution the code belongs to and nothing about the account number beside it.
Institution, not branch. Austrian bank codes identify institutions; branch detail is not derivable from an IBAN.
A monthly snapshot of a daily file — see above. as_of tells you exactly which one answered.
The LEI comes from the register, not from us. Where the OeNB publishes none, the field is null rather than back-filled from GLEIF, so what you read is what Austria published.