IBAN validation now available in Postcoder

Postcoder now validates international bank account numbers - and for UK IBANs, returns full bank and branch details too.

Taking payment details from a customer is a moment where mistakes are expensive. A mistyped account number can mean a failed payment, a delayed order or - worse - money sent to the wrong place. That's why we've added IBAN validation to Postcoder, letting you check an international bank account number the moment it's entered, before it goes anywhere near a payment.

An IBAN (International Bank Account Number) is the standard format used to identify bank accounts across many countries, helping ensure payments reach the correct destination. While the format is standardised internationally, each country has its own rules about length and structure.

The new bank/iban endpoint validates an IBAN by checking its checksum, then verifying its length and format against the country indicated by its first two characters. A German IBAN is checked against the German specification, a French one against the French, and so on.

More than a yes or no

For UK IBANs, the endpoint goes further. As well as validating the IBAN itself, it returns bank and branch details using the latest data from the Extended Industry Sort Code Directory (EISCD) - the same trusted source behind Postcoder's other bank validation endpoints.

That includes the bank and branch name, BIC codes and contact details, plus the sort code and account number extracted from the IBAN. This last part matters more than it might appear: UK domestic payment schemes like Bacs and Faster Payments don't accept IBANs, so if a customer gives you an IBAN and you want to collect a Direct Debit, you need the sort code and account number it contains. The endpoint hands you both, ready to use.

You'll also get flags telling you which payment schemes the account supports - Direct Debits, Faster Payments, CHAPS and Bacs - so you know before you start that the payment you're planning will actually work.

Why we added IBAN validation

Plenty of our customers take payments from outside the UK, and until now validating an IBAN meant either a separate provider or no validation at all. If you're already using Postcoder for address lookup, email, mobile or bank validation, you can now cover IBANs with the same API key, the same request style and the same straightforward pricing.

It also pairs naturally with the existing bank endpoints - use those when your customers give you UK account details directly, and bank/iban when they give you an IBAN.

Getting started

IBAN validation is available now for all Postcoder customers. Each request costs 1.2 credits and uses your existing API key - just point a request at the bank/iban endpoint and you're away. The docs have everything you need, including example requests and responses.

If you have any questions about the endpoint or want help integrating it, the Postcoder support team is always happy to help - just get in touch.

Note: Always verify details with the sender or recipient before setting up payments.