Is there any web service to make phone calls like Google 2-step verification? [closed]

Question

Is there any web service that provides something to make phone calls?

Let say I want to build one site where people can make phonepranks. I enter the number of my friend and when I submit the form, it calls him with a message like "7 days".

Or like google does with its 2-step verification. When you don't receive a message google gives you the option to call you and give the code.

Answer 1

I just found it. It's called hoiio and it works almost on every country. It's affordable and easy to implement.

The other options were tropo, pilvo ( I couldn't make them work) amd twilio (it doesn't work for my country).