Invoice Number Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching invoice number, 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

// Invoice Number
// ReDoS-safe | RegexVault — Finance > Financial Formats

const invoiceNumberRegex = /^[A-Z0-9\-]{4,15}$/;

function validateInvoiceNumber(input: string): boolean {
  return invoiceNumberRegex.test(input);
}

// Example
console.log(validateInvoiceNumber("INV-00001")); // 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

Invoice numbering conventions vary widely. This pattern covers the most common formats. The prefix identifies the document type (INV, SINV, PO, CN for credit note). Pad with leading zeros for sortability.