IBAN Validator live
Validates an IBAN's structure and checksum (ISO 13616 / mod-97). No, it won't tell you if there's money in it.
// response appears here| iban* | text | IBAN (spaces and lower-case are fine) | DE89 3704 0044 0532 0130 00 |
curl 'https://iban.benjamin-dreier.de/v1/validate?iban=DE89+3704+0044+0532+0130+00'{
"iban": "DE89370400440532013000",
"valid": true,
"country_code": "DE",
"check_digits": "89",
"bban": "370400440532013000",
"formatted": "DE89 3704 0044 0532 0130 00",
"length": 22,
"expected_length": 22
}OpenAPI spec → — drop it into your own client or codegen.
The IBAN Validator checks whether an International Bank Account Number is structurally valid: the right length for its country and a correct mod-97 checksum (ISO 13616). Paste an IBAN — spaces and lower-case are fine — and it tells you whether the number is plausible and returns the country code, check digits, the BBAN, and a neatly grouped format for display.
What it can't do is tell you the account exists or has money in it — structural validation is the ceiling without a live line into the banking system. That's exactly the point, and it makes a good fit for form validation, cleaning up imported payment data, or catching a fat-fingered digit before it becomes a failed transfer. I wrote up the story and the mod-97 math in this post.
| valid | the headline result: true or false |
| reason | why it failed (present only when invalid) |
| country_code | the leading two letters, e.g. DE |
| check_digits | the two-digit checksum |
| bban | the country-specific account part |
| formatted | grouped into blocks of four for display |
| length / expected_length | actual vs. required length for the country |
| DE89370400440532013000 | a valid German IBAN |
| GB29NWBK60161331926819 | a valid UK IBAN |
| FR1420041010050500013M02606 | a valid French IBAN (letters in the BBAN) |
| de89 3704 0044 0532 0130 00 | spaces and lower-case are accepted |
| DE00000000000000000000 | right length, checksum fails → valid: false |
| DE8937040044 | too short for DE → length mismatch |