What sms gateway to use for worldwide project?

Question

Notifications

Good afternoon.
There is a project, it has clients from all over the world up to China.
At certain moments, it is very critical to send a user (let's imagine that his site is unavailable) an SMS message with information, he agreed to the mailing list.
Criteria:
1) Fast delivery
2) API available
3) Low price
4) Large coverage
5) 50% of clients from Russia, CIS
6) Can be paid to an individual
Tell me which project can I use?

Answer 1

The main gag in paragraph 6, if you are considering services from Russia. Large SMS integrators are reluctant to conclude contracts with individuals, because complaints about the content of the mailing should be forwarded to the one who screwed up. And what is the demand for physics)