We are using Nobel SMS for our OTP and 2FA functionalities in our platform. What's great about it is that the codes sent to our users through the SMS are arriving lightning fast (based on the feedback received is under 5 seconds) and since we integrated Nobel SMS, the delivery rate increased significantly and our customer support is spending less time on phone number validation tickets. Their platform is easy to use and the integration went smooth. Also the pricing is very good for our type of traffic and predictable.