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google/libphonenumber

Analysis updated 2026-06-24

★ 18,008C++Audience · developerComplexity · 2/5Setup · easy

TLDR

Google's open-source library for parsing, validating, and formatting phone numbers from every country, available in Java, C++, and JavaScript.

Mindmap

mindmap
  root((libphonenumber))
    What it does
      Parse phone numbers
      Validate numbers
      Format numbers
    Features
      Type detection
      Geographic lookup
      As-you-type format
    Tech stack
      Java
      C++
      JavaScript
    Use cases
      Form validation
      Contact management
      Telecom integration
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Code map

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filefunction / class

What do people build with it?

USE CASE 1

Validate phone number fields in a signup form to check the number is real and correctly formatted for the user's country.

USE CASE 2

Parse phone number strings from user input into structured objects containing the country code and local number.

USE CASE 3

Format a stored phone number for display in international, national, or compact E.164 format.

USE CASE 4

Build a phone input field that formats itself progressively as the user types each digit.

What is it built with?

JavaC++JavaScript

How does it compare?

google/libphonenumberwled/wledhaoel/leetcode
Stars18,00818,04418,054
LanguageC++C++C++
Setup difficultyeasymoderateeasy
Complexity2/53/51/5
Audiencedevelopergeneraldeveloper

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · easy Time to first run · 30min

In plain English

libphonenumber is Google's open-source library for working with phone numbers from every country in the world. It provides implementations in Java, C++, and JavaScript. The Java version is the primary one and has been part of the Android operating system since version 4.0. The library can parse a string like "044 668 18 00" (given a country context) into a structured object containing the country code and national number. Once parsed, you can validate whether the number is actually valid for the given region, format it in various standard ways (international format, national format, or the E.164 compact format used by telephone networks), check what type of line it is (mobile, landline, toll-free, VoIP, and others), and determine the geographic area associated with the number. A utility called AsYouTypeFormatter can format a number progressively as a user types each digit, which is useful for building phone number input fields. The library also includes tools for finding phone numbers embedded in free text and for mapping numbers to carriers and time zones. It is updated roughly every two weeks with metadata changes to keep up with new number ranges around the world.

Copy-paste prompts

Prompt 1
Using google/libphonenumber in JavaScript, show me how to check that a user-entered phone number is valid for a specific country code.
Prompt 2
Write code using libphonenumber to parse the string '+44 20 7946 0958' and reformat it in E.164 format.
Prompt 3
How do I use libphonenumber's AsYouTypeFormatter to format a phone number live as the user types into an HTML input field?
Prompt 4
Show me how to detect whether a phone number is a mobile or landline using libphonenumber in Java.
Prompt 5
How do I use libphonenumber to find all phone numbers mentioned in a paragraph of free text?

Frequently asked questions

What is libphonenumber?

Google's open-source library for parsing, validating, and formatting phone numbers from every country, available in Java, C++, and JavaScript.

What language is libphonenumber written in?

Mainly C++. The stack also includes Java, C++, JavaScript.

How hard is libphonenumber to set up?

Setup difficulty is rated easy, with roughly 30min to a first successful run.

Who is libphonenumber for?

Mainly developer.

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