IBAN validation
IBAN bank account number (length table plus mod-97) — checksum: ISO 13616 mod-97-10. Free in your browser, or over the JSON API.
What it is
IBAN bank account number (length table plus mod-97). CodeCheck verifies three things separately — format, length and check digit — and returns the expected and provided check digit, so a failed value tells you exactly what is wrong instead of just saying no.
Algorithm
ISO 13616 mod-97-10. The answer is derived from the value itself, with no database lookup and no third-party call, so it is deterministic, fast and privacy-safe.
Examples
| Value | Result | Expected | Provided |
|---|---|---|---|
| DE89370400440532013000 | valid | — | 89 |
API
curl "https://<your-worker>.workers.dev/v1/validate/iban/DE89370400440532013000"
This type has a single trailing check digit, so CodeCheck can also compute it:
GET /v1/complete/iban/{body}
Try it in the browser demo — the demo runs the same code offline.