How to implement micropayments transparently tied to a cell phone account in a game application?

Question

Monetization

Steam API do not offer.
Interested in clear descriptions with which provider and on which API this can be implemented.

Answer 1

Either buy a short number (expensive) or use the services of a content provider , of which there are a lot and each has its own api.
The payment scheme usually looks like this for the client - he enters a phone number, he receives a code in SMS, he enters this code on the form on the site, all payment is withdrawn / subscription is connected. Less often, the OpSoSs themselves stir up automatic subscription connections (legally also through partners, but I have no idea how much it costs, it seems EXPENSIVE) just for a click or viewing an image in a mobile browser.
The content provider market is a gray market, wild commissions (30% - easy), a lot of scammers, with the support of mobile operators (most likely these are the same persons), have spoiled the reputation of a quite good payment acceptance system. Accordingly, customers are usually narrow-minded people, either by mistake or simply do not think / do not read the conditions / buy a service that is not worth it
( how can you buy a joke reading service in 2019? for 10 rubles a day! ).
Use the usual payment operators, which offer mobile payment as one of the options, i.e. the client sees on the site which payment how much it costs him and chooses the one that is convenient for him.