My website needs verifying cell phone number, because the rule of the website demands one account for one person only, but someone registers many accounts, and I can not ban him since he has many IPs and can register more new account.
Registering my website needs email-address only, and I think verifying cell phone number can achieve the goal for one account one person only. However, I find directly verifying cell phone number all over the world for website is very trouble, so I need suitable email-service, so I can only restrict the format of registering-email to verify cell phone number. Here are my demands:
1. I need to verify any cell phone number all over the world, so the email account name is just the cell phone number with country calling codes, which means that users can't use number name to register email, his number name can only be his cell phone number. For example, if one person's cell phone number is +45 5xxx4740, then the email-address is the format of 455xxx4740@domain-name. My website can get the number name 455xxx4740 of the email-address. The email-service can allow users to register any alpha name (such as nickname@domain-name) but number name(such as 818828883@domain-name) must be the actual cell phone number.
2. I find many websites offer SMS Receive Service (for example, smsreceivefree ).But I need the person who registers my websites uses his own cell phone number. So the email-service must have the effective means for this purpose. The best way is requesting user sends SMS code to the verifying-phone-number, not receiving SMS code. If the email-service bans all SMS proxy phone-number, maybe receiving SMS is also effective, but I think banning all SMS proxy is very hard.
3. The email-service must be long-term stable. I need the email-service can be used for many years. And the service is the cheaper the better. If there is free service, it is the best.

1 Answer 1


Yes, Twilio provides a free-as-in-beer phone number lookup/validator service via API. https://www.twilio.com/lookup

Here is the specific verify API w/ demo code- https://www.twilio.com/docs/verify/api

  • 2
    Twilio free as in "free beer" seems to be only for format check.
    – witrak
    Sep 10, 2018 at 13:21
  • Are you sure? To me, this looks like you can have a 'phone number verified by sending it a PIN by voice or SMS which is has to enter at your site. Very nice! Oct 11, 2018 at 10:53

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