Brazilian CEP (Código de Endereçamento Postal) Regex for Go

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 Go. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Go project — whether you're validating in a Gin handler, a gRPC service, or a command-line tool.

Go Implementation

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

package validation

import "regexp"

var brazilianCepCdigoDeEndereamentoPostalRe = regexp.MustCompile(`^([0-9]{5})-?([0-9]{3})$`)

func ValidateBrazilianCepCdigoDeEndereamentoPostal(s string) bool {
    return brazilianCepCdigoDeEndereamentoPostalRe.MatchString(s)
}

// Example
// fmt.Println(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 Go developers because Go's RE2 engine is inherently safe from catastrophic backtracking, but this pattern has been additionally verified for correctness. 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.