Slovak bank code lookup — the NBS prevodník

Slovakia calls it a kód platobného styku, a payment system code: four digits in positions 5–8 of an SK IBAN, ahead of a six-digit account prefix and a ten-digit account number. The register behind it is the Národná banka Slovenska, Directory of identification codes for the domestic payment system — the prevodník — and the NBS is the authority that allocates those four digits to the providers of the domestic payment system.

It is the smallest register we hold: 38 codes for the whole country. That is not a coverage gap, it is the size of the Slovak payment system, and it is why every code has its page rather than a selected batch.

One call

curl -X POST https://api.ibanforge.com/v1/iban/validate \
  -H "Content-Type: application/json" \
  -d '{"iban": "SK3112000000198742637541"}'

{
  "valid": true,
  "bic": null,
  "bank_code_check": {
    "value": "1200",
    "status": "not_in_register",
    "reason": "not_allocated",
    "match": null,
    "register": "Národná banka Slovenska, prevodník of identification codes for the domestic payment system",
    "authoritative": true,
    "as_of": "2026-05"
  }
}

That IBAN is not a typo either. SK31 1200 0000 1987 4263 7541 is Slovakia's official example IBAN, the one in the ISO 13616 registry and in half the test suites on the internet — and its payment code 1200 is in the prevodník nowhere. The structure is perfect (valid: true), the allocation is empty (not_in_register), and both statements are true at once. It is the same pattern as Austria's AT61 1904 3002 3457 3201, which we wrote up in the world's two favourite example IBANs point at bank codes that don't exist.

What `not_in_register` means here

authoritative: true is what gives that "no" its weight: the reference set consulted is the register that hands out Slovak payment codes, so an absence is the allocation authority's own verdict rather than a gap in our data.

reason: "not_allocated" is the machine-readable half — the one value in that field which licenses stopping a payment. Where we fall back to the composite BIC map, an absence proves nothing and the reason says so instead.

What the prevodník publishes

Field	In the Slovak register	Note
`name`	yes	the payment service provider, verbatim — Slovak diacritics as published, never transliterated
`bic`	for 34 of 38 codes	the 8-character BIC the register pairs with the code
`street` / `post_code` / `town`	no	the directory publishes no address at all; the fields are `null` because that is what Slovakia publishes, not because we lost them
`lei`	no	not in this register

Four codes are allocated and carry no BIC (8191, 8400, 9950, 9956). Those answer verified with bic: null — the institution exists, the register simply publishes no BIC for it. Existence and BIC availability are separate questions, and the response keeps them separate.

Eight Czech banks with a Slovak code

Fio banka, J&T, TRINITY, PPF, MONETA, Air bank, CREDITAS and Partners hold Slovak payment codes and publish Czech BICs (FIOBCZPP, AGBACZPP, and so on). The register lists them, so we serve them: a Slovak IBAN on code 0600 really does route to a bank whose BIC ends in CZPP. A validator that quietly required the BIC country to match the IBAN country would deny all eight.

Note also that Fio and J&T each appear twice, under a Slovak branch code and a Czech parent code with different BICs, and that 3100 is Prima banka Slovensko's code for running payments — a wind-down code kept alongside its live 5600. The register says so; we serve the register's own words.

Freshness and the citation

The NBS publishes the prevodník as a numbered edition with its own effective date, and we refresh monthly. as_of therefore carries the register's date, not our refresh month — dating it with ours would claim a freshness the NBS never stated.

Slovak data is reproduced under the NBS site terms (Podmienky používania), which permit storing, reproducing and reusing published information without prior consent provided the Národná banka Slovenska is named as the source and the file is not altered. Both conditions travel with every answer: bank_code_check.register and bic.source name the authority and the edition, as_of carries its effective date, and names are served exactly as published. Reuse of these fields carries the same conditions onward. The full provenance note is on data sources.

The honest limits

We check the payment code, never the account or its holder. A verified Slovak code names the institution the code belongs to and says nothing about the sixteen digits beside it.
Institution, not branch. The six-digit account prefix is a bank-internal field; it is not a branch code the register enumerates, and it is never used to deny.
No address, and none invented. See the table above.
No deletion flag. Unlike the Bundesbank file, this register publishes no retirement marker and no successor code — a provider that leaves simply disappears from the next edition, so a Slovak not_in_register never comes with a re-papering hint.