International Phone with Formatting (Liberal) Regex for Go

What this pattern does

This page provides a well-structured, multi-part regular expression for matching international phone with formatting (liberal), 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

// International Phone with Formatting (Liberal)
// ReDoS-safe | RegexVault — Localization > Phone Numbers

package validation

import "regexp"

var internationalPhoneWithFormattingLiberalRe = regexp.MustCompile(`^\+?[1-9][0-9]{0,2}[\s.()-]{0,2}[0-9][0-9\s.()-]{5,15}[0-9]$`)

func ValidateInternationalPhoneWithFormattingLiberal(s string) bool {
    return internationalPhoneWithFormattingLiberalRe.MatchString(s)
}

// Example
// fmt.Println(ValidateInternationalPhoneWithFormattingLiberal("+1 (212) 555-0100")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Phone Numbers 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

Liberal pattern for accepting phone numbers from international forms. Strip all non-digits except leading + before storing. Normalize to E.164 for storage and comparison.