IBAN-Formatted Account Display Regex for JavaScript

What this pattern does

This page provides a well-structured, multi-part regular expression for matching iban-formatted account display, ported and verified for JavaScript. Financial data validation has zero tolerance for false negatives — a missed invalid entry can corrupt downstream calculations. The snippet below is ready to drop into your JavaScript project — whether you're validating in an Express middleware, a Next.js API route, or a client-side form.

Javascript Implementation

// IBAN-Formatted Account Display
// ReDoS-safe | RegexVault — Finance > Financial Formats

const ibanformattedAccountDisplayRegex = /^[A-Z]{2}[0-9]{2}(?:\s[A-Z0-9]{4})+(?:\s[A-Z0-9]{1,4})?$/;

function validateIbanformattedAccountDisplay(input: string): boolean {
  return ibanformattedAccountDisplayRegex.test(input);
}

// Example
console.log(validateIbanformattedAccountDisplay("GB29 NWBK 6016 1331 9268 19")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Financial Formats category and carries a ReDoS-safe certification. That matters for JavaScript developers because especially critical in long-running Node.js event loops where a ReDoS vulnerability can block the entire process. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Display-formatted IBANs use spaces every 4 characters (with the final group being 1-4 chars). Strip all spaces before any processing, lookup, or comparison. Store IBANs without spaces.