If you want to write an app that you can move between multiple providers or run yourself (ie, it's legitimately portable), and/or want to choose your own SIP carrier, feel free to use Cloudvox [1].
Every app gets a SIP URI that any carrier's phone numbers can route to [2]. Our prices are much lower for third-party SIP calls, since we don't have telecom costs. It's free to sign up, as are local SIP phone calls (like between your SIP phones and your apps).
Apps use PHP-AGI, Adhearsion, Asterisk-Java, or any other Asterisk-compatible client library [3], or there's a HTTP/JSON interface [4].
We're fundamentally a cloud-scale Asterisk hosting service, like Heroku for phone/SMS services, so we aren't trying to get people to marry our API. If we don't do our jobs, take your app with you.
Comments
If you want to write an app that you can move between multiple providers or run yourself (ie, it's legitimately portable), and/or want to choose your own SIP carrier, feel free to use Cloudvox [1].
Every app gets a SIP URI that any carrier's phone numbers can route to [2]. Our prices are much lower for third-party SIP calls, since we don't have telecom costs. It's free to sign up, as are local SIP phone calls (like between your SIP phones and your apps).
Apps use PHP-AGI, Adhearsion, Asterisk-Java, or any other Asterisk-compatible client library [3], or there's a HTTP/JSON interface [4].
We're fundamentally a cloud-scale Asterisk hosting service, like Heroku for phone/SMS services, so we aren't trying to get people to marry our API. If we don't do our jobs, take your app with you.
[1]: http://cloudvox.com/
[2]: http://help.cloudvox.com/faqs/getting-started/incoming-call-...
[3]: http://help.cloudvox.com/faqs/getting-started/agi-or-http
[4]: http://help.cloudvox.com/faqs/getting-started/http-api