Brazilian CEP (Código de Endereçamento Postal) Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching brazilian cep (código de endereçamento postal), 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

// Brazilian CEP (Código de Endereçamento Postal)
// ReDoS-safe | RegexVault — Localization > Postal Codes

const brazilianCepCdigoDeEndereamentoPostalRegex = /^([0-9]{5})-?([0-9]{3})$/;

function validateBrazilianCepCdigoDeEndereamentoPostal(input: string): boolean {
  return brazilianCepCdigoDeEndereamentoPostalRegex.test(input);
}

// Example
console.log(validateBrazilianCepCdigoDeEndereamentoPostal("01310-100")); // 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

Capture group 1: region+district (5 digits), group 2: sector (3 digits). Brazilian CEP ranges: 01000-09999 (São Paulo capital), 20000-28999 (Rio de Janeiro state), 70000-72799 (Brasília). Correios provides the authoritative database.