Canadian Postal Code Regex for Go

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching canadian postal code, 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

// Canadian Postal Code
// ReDoS-safe | RegexVault — Localization > Postal Codes

package validation

import "regexp"

var canadianPostalCodeRe = regexp.MustCompile(`^([ABCEGHJKLMNPRSTVXY][0-9][ABCEGHJKLMNPRSTVWXYZ])\s?([0-9][ABCEGHJKLMNPRSTVWXYZ][0-9])$`)

func ValidateCanadianPostalCode(s string) bool {
    return canadianPostalCodeRe.MatchString(s)
}

// Example
// fmt.Println(ValidateCanadianPostalCode("K1A 0B1")) // 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

First letter identifies the province. Invalid first letters: D, F, I, O, Q, U, W (excluded because they resemble digits in some fonts or were reserved). The letter D and I are also excluded from all positions for readability.