Swiss Postleitzahl (PLZ) Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching swiss postleitzahl (plz), ported and verified for JavaScript. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. 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

// Swiss Postleitzahl (PLZ)
// ReDoS-safe | RegexVault — Localization > Postal Codes

const swissPostleitzahlPlzRegex = /^([1-9][0-9]{3})$/;

function validateSwissPostleitzahlPlz(input: string): boolean {
  return swissPostleitzahlPlzRegex.test(input);
}

// Example
console.log(validateSwissPostleitzahlPlz("1000")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Postal Codes 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

Swiss PLZ ranges: 1000-1999 (Vaud/Romandy), 2000-2999 (Neuchâtel/Jura), 3000-3999 (Bern), 4000-4999 (Basel), 5000-5999 (Aargau), 6000-6999 (Lucerne/Ticino), 7000-7999 (Graubünden), 8000-8999 (Zurich), 9000-9999 (St. Gallen/Appenzell).