A quality SMS gateway for two-factor authentication?

Question

Computer networks

Recommend a quality SMS gateway to use as a two-factor authentication on the site. Basic requirements:
- Conscientiousness and name. This is a very important point. We would REALLY not want our clients to end up in the SMS mailing lists.
- Letter name of the sender (the ability to send not from an incomprehensible number, but on behalf of our service).
- Adequate prices (preferably up to 1r for SMS to numbers in the Russian Federation)
- Ability to send SMS to numbers in Europe / Asia. The main audience of the service is Russian-speaking, but there are enough users from Europe.

Answer 1

I use sms.ru for my small tasks .
So far, there haven't been any problems.

Answer 2

SMS Pilot

Answer 3

for the corporate sector and large mailing lists see sms.ua