This project will show you one way to validate phone number inputs with the intl-tel-input library and Twilio's Lookup API. For a production use case we recommend adding phone verification, which is a best practice for collecting phone numbers from your users in order to make sure they have control of the number.
Create a .env file and add your environment variables found in the Twilio console
cp .env.example .ev
Then install the dependencies and run with npm:
npm install
npm start
Navigate to http://localhost:3000/index.html