Visa Card Number Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching visa card 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

// Visa Card Number
// ReDoS-safe | RegexVault — Finance > Card Numbers

const visaCardNumberRegex = /^4[0-9]{12}(?:[0-9]{3})?$/;

function validateVisaCardNumber(input: string): boolean {
  return visaCardNumberRegex.test(input);
}

// Example
console.log(validateVisaCardNumber("4111111111111111")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Card Numbers 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

Visa uses prefix 4. 13-digit Visa cards are legacy (some still in circulation). 16-digit is standard. Luhn validation required separately. Input should have spaces/hyphens stripped before matching.