IBAN validation API

$0.01 per call · failed calls are never charged · no account or subscription: pay per call with a card key or USDC

Check an IBAN's format, its country-specific length and its mod-97 check digits, and return it formatted in groups of four. Use before saving bank details or paying out.

When to use it

Run it free (25 free calls) Buy credits by card (from $1) Example result (JSON)

Try it with your own inputs

The IBAN, spaces allowed

Uses one of your 25 free calls. Nothing is charged, and a call that fails is not counted.

Inputs

NameTypeDescription
iban (required)stringThe IBAN, spaces allowed

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://tools.funwords.eu/validate/iban?iban=SE45%205000%200000%200583%209825%207466"

Or one of your 25 free calls, no key:

curl "https://tools.funwords.eu/validate/iban?iban=SE45%205000%200000%200583%209825%207466&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "iban": "SE4550000000058398257466",
  "country": "SE",
  "valid": true,
  "reasons": [],
  "formatted": "SE45 5000 0000 0583 9825 7466"
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is validate_iban, and the first 25 successful calls are free:

https://tools.funwords.eu/mcp

Questions

Does it confirm the account exists?

No, it checks the country format and checksum only.

How do I pay?

Each successful call costs $0.01; failed calls are not charged. The first 25 calls are free. Then pay with card credits (from $1; the key goes in an Authorization header or, for clients that can only fetch a URL, as api_key= in the URL) or per call in USDC over x402 or MPP. No account is needed.

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