SMS registration like in the mobile app: whatsapp

Question

I\'m wondering how these sms-registration mechanisms work. I searched on the internet, but the problem is there are so much sms-providers which want to sell online-sms servi

Answer 1

The basic fundamentals are :

1. Generate a random code in your app on the device. Ask user for his mobile number.
2. Send this code and mobile number to your application running on server.
3. Call the sms gateway API to send the code as a message to the mobile number specified.

There are many SMS gateway providers. You can search on google. Most of them also provide a tutorial for using their API in various programming languages. The cost is mostly based on per message and generally they are to be bought in the form of package of number of SMSes.