How to organize SMS distribution on your equipment, with API capabilities?

Question

Telephony

For several own services in 2 different countries, it is necessary to organize SMS distribution, transactional with registration confirmation, various notifications, marketing. It is necessary to reduce the cost of SMS as much as possible, services for sending SMS are not suitable. It also requires an API so that each site can send SMS depending on the given scenario.
There is a solution on how to make mailings using 3G modems and special software, but this is not quite right, because. there is only manual mailing, no API. And it doesn't work, unfortunately.
I found information that this can be organized using Asterisk, a SIM-bank and a pair of VoIP GSM gateways supplied in different countries. But, because I am neither really familiar with telephony, nor with network administration, here I am at a loss how all this can be correctly described in the TOR, and, in fact, what kind of specialist should I look for. Asterisk programmer? And where is it more profitable, and what equipment to buy in 2020?

Answer 1

Asterisk is needed if you need calls.
Look towards the goip gateway. They have an SMS server on Linux with api, several gateways can be connected to one server.