What the validator checks
Every country publishes a numbering plan that defines which number ranges exist, how long they are and what they are used for. The validator compares your number against the official plan data maintained in Google's open-source libphonenumber project, the same data used by Android and many messaging apps.
- • Whether the number belongs to an allocated range in its country
- • Whether its length is possible for that country
- • The line type: mobile, landline, VoIP, toll-free, premium rate and more
- • The correct national, international and E.164 formats
Valid vs. active
A valid number fits the numbering plan; an active number is actually connected to a subscriber today. Validation is instant and offline, so it cannot tell you whether a number is switched on or who owns it. For that, run a reverse phone lookup or a carrier lookup.
Why validate phone numbers?
People validate numbers before saving a contact, before sending money to a marketplace seller, or to understand an unfamiliar international number. Businesses validate numbers in sign-up forms to avoid typos and to make sure SMS codes reach a mobile phone rather than a landline.