International Phone with Formatting (Liberal) Regex for Java

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 Java. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Java project — whether you're validating in a Spring Boot controller, a Jakarta EE service, or a standalone utility class.

Java Implementation

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

import java.util.regex.Pattern;

public class InternationalPhoneWithFormattingLiberalValidator {
    private static final Pattern PATTERN =
        Pattern.compile("^\\+?[1-9][0-9]{0,2}[\\s.()-]{0,2}[0-9][0-9\\s.()-]{5,15}[0-9]$");

    public static boolean validate(String input) {
        return PATTERN.matcher(input).matches();
    }

    // Example
    public static void main(String[] args) {
        System.out.println(validate("+1 (212) 555-0100")); // true
    }
}

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Phone Numbers category and has been checked for ReDoS risk. That matters for Java developers because critical in Java applications since the JVM regex engine uses backtracking and is susceptible to ReDoS without careful pattern design. 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.