Guides · API

IBAN validation API

IBAN validation for payout, invoicing and onboarding agents: ISO 13616 length per country, ISO 7064 mod-97 checksum (catches typos), SEPA membership, and for Dutch IBANs the bank (ING, ABN AMRO, Rabobank, bunq...). Does not confirm the account holder.

0.001 USDC per call · GET /v1/iban/check · free preview at /v1/iban/check/preview

Parameters

Name	Required	Description
`iban`	yes	IBAN, spaces allowed, e.g. NL91 ABNA 0417 1643 00

Example request

curl "https://factline.dev/v1/iban/check?iban=NL91ABNA0417164300"
# 402 Payment Required: pay with an x402 client (USDC on Base), or send
# Authorization: Bearer <your Factline API key>

Example response

{
  "iban": "NL91 ABNA 0417 1643 00",
  "valid": true,
  "reasons": [],
  "country": "NL",
  "sepa": true,
  "bank_code": "ABNA",
  "bank": "ABN AMRO",
  "explain": {
    "valid": "Format, length and the ISO 7064 mod-97 checksum are correct. This does not prove the account exists or who holds it (use the Dutch 'Verificatie van Betalingsontvanger' at your bank for name matching)."
  },
  "source": "ISO 13616 IBAN structure; Dutch bank codes from the Betaalvereniging BIC list"
}

Use it from an AI agent

Agents with an x402 wallet call the URL directly and pay per request. Assistants that speak MCP connect to https://factline.dev/mcp. Full reference: docs, OpenAPI, llms.txt. Businesses: API keys with a free trial.

Questions

How much does the IBAN validation cost?

0.001 USDC per call, paid per request with x402 (no account), or included in a Factline API key plan with a free trial. Calls that fail are not charged.

Can I try it for free?

Yes: GET /v1/iban/check/preview with the same parameters validates your input and shows what the paid answer contains, at no cost.

Where does the data come from?

Official public registers and open data, named with their licence in every response (source field) and at /.well-known/x402-license-provenance.