There are two options for validating phone numbers, the Twilio Lookup API and the intl-tel-input plugin. The Twilio Lookup API is a free service that provides updated phone number validity data and can also check for line type or carrier. However, it requires more code and a network request. On the other hand, the intl-tel-input plugin provides a wrapper around Google's libphonenumber to help detect valid and invalid phone numbers, but its validation rules may change and lock out some valid users. Both options provide similar results, with the Lookup API being preferred for its use of an existing API to verify phone numbers. Validating a phone number is only one step in preventing fraud and ensuring account security, as it's recommended to also implement phone verification methods such as sending a one-time passcode (OTP) to the provided phone number.