German PLZ (Postleitzahl) Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching german plz (postleitzahl), 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

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

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

function validateGermanPlzPostleitzahl(input: string): boolean {
  return germanPlzPostleitzahlRegex.test(input);
}

// Example
console.log(validateGermanPlzPostleitzahl("10115")); // 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

German PLZ ranges: 01xxx-09xxx (east), 10xxx-14xxx (Berlin/Brandenburg), etc. The code 00000 is explicitly invalid. Also used in Austria (4 digits — different pattern) and Switzerland (4 digits). Use this only for Germany.