US Social Security Number (SSN) — PII context Regex for JavaScript

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching us social security number (ssn) — pii context, ported and verified for JavaScript. Identity and credential patterns need both correctness and safety, since they're frequent targets for adversarial input. 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

// US Social Security Number (SSN) — PII context
// ReDoS-safe | RegexVault — Identity & PII > Financial PII

const usSocialSecurityNumberSsnPiiContextRegex = /^(?!(?:000|666|9[0-9]{2})-|[0-9]{3}-(?:00|[0-9]{3}-0{4}))(?:[0-9]{3})-(?:[0-9]{2})-(?:[0-9]{4})$/;

function validateUsSocialSecurityNumberSsnPiiContext(input: string): boolean {
  return usSocialSecurityNumberSsnPiiContextRegex.test(input);
}

// Example
console.log(validateUsSocialSecurityNumberSsnPiiContext("123-45-6789")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > Financial PII 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

Intentionally included in Identity & PII batch in addition to Finance batch (fin-tax-01) to ensure Aurora surfaces the appropriate data handling warnings in both contexts. SSN is the most sensitive financial PII in the US — its exposure enables identity theft.