Check any IBAN. Calculate German ones.

Offline, snapshot-based IBAN validation for every SEPA country — structure and checksums, bank and BIC resolution from the Bundesbank registry, EPC SEPA reachability — plus fail-closed German BLZ + Kontonummer → IBAN calculation against the complete Bundesbank rulebook. Clean JSON, versioned data, never a guess.

API reference OpenAPI

Try it — live verdicts

These call the free, rate-limited demo lanes of the API — the same engine behind every endpoint. Real answers, no fabrication.

Check an IBAN (any SEPA country)

Try:

Calculate a German IBAN from BLZ + Kontonummer

Try:

What you can call

Free while it's in beta — no key, no account. The full, always-current list lives in the OpenAPI document.

Method	Endpoint	What it returns
POST	/v1/check	Full layered IBAN check — structure, bank, checksums, BIC/LEI, SEPA reachability
POST	/v1/batch	Check up to 100 IBANs in one request, input order kept
POST	/v1/calculate/de	German BLZ + Konto → the rulebook-correct IBAN, or a refusal — never a guess
GET	/v1/bank/de/{blz}	Bank-registry row incl. BIC, Prüfziffer method and the IBAN rule key
GET	/v1/health	Liveness, pinned engine version and every data snapshot date (free)
GET	/v1/reason-codes	Machine-readable reason-code catalog for both pipelines (free)

For agents

Point any HTTP client at the base URL — no key, no signup. Every verdict is computed offline against pinned data snapshots, and every response carries data_versions and attribution, so an agent always knows the source and freshness. Calculation is fail-closed: the rulebook-correct IBAN or a machine-readable refusal.

# no API key — one call, clean JSON
curl -s -X POST https://iban.api.chrisked.de/v1/check \
  -H 'content-type: application/json' \
  -d '{"iban":"DE89 3704 0044 0532 0130 00"}'

# fail-closed German BLZ + Konto → IBAN
curl -s -X POST https://iban.api.chrisked.de/v1/calculate/de \
  -H 'content-type: application/json' \
  -d '{"bank_code":"37040044","account":"532013000"}'

Prefer a machine-readable contract? The reference (Scalar) and the OpenAPI JSON describe every endpoint and error shape. More services in the family live at api.chrisked.de.