* [International Telephone Input v29.2.0](https://github.com/jackocnr/intl-tel-input) – JavaScript plugin for entering and validating international telephone numbers with features like country detection and number formatting.

* [Phonelib v0.10.27](https://github.com/daddyz/phonelib) – Ruby gem for phone number validation and formatting using Google libphonenumber data.

* [phone 3.1.72](https://github.com/AfterShip/phone) – Library to normalize and validate mobile phone numbers into E.164 format with country-specific rules.