Looking for a VoIP service provider

Question

I am looking for a VoIP service my application can use to call landlines and mobile phones.

What I need:

• I would generate an audio file and send it to the service. The service would then place the call and play the audio file.

Other features that would be a plus:

• TTS (I send text and the service converts it to audio for me)
• Ability to receive DTMF responses

Any suggestions?

Answer 1

Try City Watch by Avtex. It does all those things.

-Barnzy

Answer 2

For calling and playing audio files you could have a look at the Asterisk server. Altough this is not an external service which I think you're looking for, it could be used to connect to a VoIP-provider and play the file.

Answer 3

After quite a bit of digging I am going to give CallFire a try.

It looks very promising.

Answer 4

Try Twilio. It is amazingly easy to use and does all that you want: play audio files, say text, and gather DTMF input. They've even got some speech to text transcription now.