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Validate an IBAN from code

Check an IBAN's checksum, country length and format with one call. No account needed, nothing is sent to a bank.

Typos in IBANs cause failed payments and manual follow-up. This endpoint runs the ISO 13616 checks locally: the mod-97 checksum, the registered length for the country and the format. It returns the normalised and grouped number and tells you which check failed.

It does not tell you whether the account exists or who owns it. Use it to catch mistakes at the form, before a payment is attempted.

The calls

Each call returns 402 with the price until a payment is attached; an x402 client pays and retries automatically. Calls that fail are not charged. See Get started and the guide for bots and agents for code.

iban-validate $0.003 per call

Validate an IBAN offline: ISO 13616 checksum (mod 97), registered length for the country, and a normalised and grouped format.

curl -i "https://api.ambolt.dev/v1/iban-validate?iban=DK50+0040+0440+1162+43"

{
  "input": "DK50 0040 0440 1162 43",
  "normalized": "DK5000400440116243",
  "checkedAt": "2026-10-02T21:35:47.671Z",
  "valid": true,
  "country": "DK",
  "length": 18,
  "countryKnown": true,
  "grouped": "DK50 0040 0440 1162 43",
  "checkDigits": "50",
  "bban": "00400440116243"
}

Questions

Does it check that the account exists?

No. It only validates the number itself.

Which countries are supported?

All countries in the IBAN registry. For countries it does not know, only the checksum is checked and the response says so.

Is the IBAN stored?

No. The check is computed and discarded.

Use it from an AI agent

Every call is also an MCP tool: add https://api.ambolt.dev/mcp to your agent's server list.