Portuguese Código Postal (CP4-3) Regex for Go

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching portuguese código postal (cp4-3), 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

// Portuguese Código Postal (CP4-3)
// ReDoS-safe | RegexVault — Localization > Postal Codes

package validation

import "regexp"

var portugueseCdigoPostalCp43Re = regexp.MustCompile(`^([1-9][0-9]{3})-([0-9]{3})$`)

func ValidatePortugueseCdigoPostalCp43(s string) bool {
    return portugueseCdigoPostalCp43Re.MatchString(s)
}

// Example
// fmt.Println(ValidatePortugueseCdigoPostalCp43("1000-001")) // 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

Portugal uses a CP4+3 (7-digit total, hyphen-separated) system. 1xxx (Lisbon), 4xxx (Porto), 8xxx (Algarve). CTT (Correios de Portugal) maintains the authoritative database. The hyphen is mandatory, unlike many other countries.