What are the ways to send SMS when registering in a mobile application?

Question

Mobile development

Hello. When developing the application, we faced a rather simple issue: when registering, the user indicates his phone number and receives a digital code for it via a regular SMS. I got acquainted with the tariffs of services for sending SMS, on average, one SMS costs about 2-2.5 rubles. I asked myself a question - is it really only for registration, say 100 thousand users, that they will have to spend 200,000 rubles? Quite an impressive cost item is obtained. What if it's a free app? Is there any way to save on this item?

You can not talk about the decrease in cost with an increase in the number of SMS, this is understandable. But the savings there are not significant if you do not send millions of such SMS a month.

Answer 1

What if it's a free app? Is there any way to save on this item?

Do not use SMS for authorization.