BulkSMS.com is very simple but very effective, reliable, easy to use and reasonably priced with a pay per message system. What makes it an essential integration, in my opinion, is that it serves hundreds of countries where most SMS service providers only offer SMS messaging to a handful of countries. For me specifically (stay in South Africa) this is possibly the only SMS service provider that I can use.
I am not sure if they work with webhooks but I'm sure they would be happy to provide some if you ask them (it would be a good business decision for them) and they do work with API.
I am not sure if they work with webhooks but I'm sure they would be happy to provide some if you ask them (it would be a good business decision for them) and they do work with API.