SWIFT / BIC Code Regex for JavaScript

What this pattern does

This page provides a well-structured, multi-part regular expression for matching swift / bic code, 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

// SWIFT / BIC Code
// ReDoS-safe | RegexVault — Finance > Bank Identifiers

const swiftBicCodeRegex = /^[A-Z]{4}[A-Z]{2}[A-Z0-9]{2}(?:[A-Z0-9]{3})?$/;

function validateSwiftBicCode(input: string): boolean {
  return swiftBicCodeRegex.test(input);
}

// Example
console.log(validateSwiftBicCode("DEUTDEDB")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Bank Identifiers 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

Structure: 4-char bank code + 2-char country code + 2-char location code + 3-char branch code (optional, XXX = primary office). 8-char BICs are treated as 11-char with XXX suffix.