Programmatically confirm the existence of a mobile number

Question

How do I confirm that a phone number is legit, or that it is connected? I want to prevent users signing up with bogus numbers.

Is there a way to programmatically make a call or something? Or find out if the phone is alive, connected?

Answer 1

The only way you can be sure that the phone number is actually connected is to send them a text-message with a unique verification-key and then have them enter that in your web-form.

Answer 2

Check out VoiceXML. That's a service that allows you to interact with a caller by reading and writing XML.

Also checking if a number is legit or connected isn't the same as proving that's the user's phone number. They could be entering a number of someone else that exists, or even a random phone number that happens to work.

Answer 3

This depends heavily on the country the mobile number is in.

I know a SMS Gateway service in Germany, for example, that checks out whether a number is connected (at least for german numbers, maybe for other european countries too) as an addition to their SMS delivery services. It costs a few cents per poll.

You would have to check with SMS gateways around the world to see what they can offer in that department.

The safest and simplest, as Espo says, is certainly to just send a confirmation SMS.