ISO 639-1 Language Code Regex for Go

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching iso 639-1 language 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

// ISO 639-1 Language Code
// ReDoS-safe | RegexVault — Localization > Locale & Language

package validation

import "regexp"

var iso6391LanguageCodeRe = regexp.MustCompile(`^[a-z]{2}$`)

func ValidateIso6391LanguageCode(s string) bool {
    return iso6391LanguageCodeRe.MatchString(s)
}

// Example
// fmt.Println(ValidateIso6391LanguageCode("en")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Locale & Language 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

ISO 639-1 codes are always lowercase 2 letters. Examples: en=English, zh=Chinese, es=Spanish, ar=Arabic, hi=Hindi, ja=Japanese, ko=Korean. Not all languages have ISO 639-1 codes — use ISO 639-3 (3-char) for less common languages.