Hello! We need to integrate an SMS gateway into our app for user phone verification. As we are just starting, we are searching for the most affordable/best price/performance option for SMS gateway to verify client phone numbers with the code, maybe you can suggest something between those two or maybe something else. We are planning to do business in Europe
Twilio is the leader. Strong API, excellent documentation and reliable service. I suggest Nexmo since their API has smaller learning curve, offering better prices and also reliable solution. Also Nexmo offers more call per sec. 3 vs 2 and 2, out of the box. Good luck
Twilio might be not cheapest, but they have awesome documentation (a lot of examples), easy to use API and libraries. I think it's a very good product to start. If the bill will become too heavy, you can shop around for economical options.