[jedsmith]

FreePBX/Asterisk is a good alternative to this, if a pain to administer. Twilio seems great for a request/response Web app, but going much further than that seems like it'd be a challenge (by design; Twilio seems to emphasize that model and simplicity).

Rather than have Twilio hand off to your 'office number' for extensions and voicemail and such, you could just have both in the same place, which is the Asterisk approach.

I'd be interested to hear if anybody has pulled off extensions and voicemail using the Twilio system. I've never used it, but based upon a quick glance at the API, it seems like it'd be doable...also, thank you for the inspiration to do something with Twilio. Signing up tonight.

[patio11]

They have a full voicemail & whatever thing with a web console for administration, as an OSS app, if you like that.

http://www.openvbx.org/

I don't actually use it, but I like the basic idea: spend your expensive programming time on places where your unique contribution adds value to the business. Common infrastructure code, on the other hand, is like a web server: download the appropriate bit of OSS, drop it in, go back to doing valuable work.

(I do my voicemail with a Twimlet, which is a less powerful version of the same idea: here's the minimum viable voicemail-to-email script, just copy/paste this URL into your config and you're good to go.)

[runT1ME]

Just know that even though the front end is Open source (and looking pretty awesome might I add), the backend telco stuff is tied to twilio which means you'll be paying their usage fees.

Unlike other open source solutions such as Asterisk or Freeswitch (which both suck in their own ways) where you can buy your own VoIP trunking/termination service from any number of companies and negotiate your own pricing.

Tropo has Twilio like functionality and some out of the box features for pbx-ing, but they allow you to either run hosted, or if I'm not mistaken, purchase their own backend telco engine and run in your own network with your own trunking provider.

[listrophy]

Another option is FreeSWITCH, an open-source telephony platform with development led by a Barracude Networks guy. I only learned about it yesterday, so I can't make a recommendation. http://www.freeswitch.org/

[chrishaum]

I used FreeSWITCH extensively for the telephony for some spoken language processing research. It is easily customizable, but has sensible defaults and is quite full-featured. Awesome software - I highly recommend it.

[runT1ME]

I'm curious why you feel the request/response model doesn't scale to more complex apps. SIP itself is request/response based, and telecom in general also is.

Their API may be lacking certain features, (I'm not sure you can do fine grained control of individual call legs) but is there a reason you don't like the request/response model?

[jedsmith]

I didn't mean that I don't like the request/response model. I meant going beyond that, by which I meant voicemail, hold music, extensions, conference calls, and so on, seems like it would be difficult to implement with the Twilio model. That's all.

If you don't need those, this looks killer. Otherwise, might as well just bite the bullet and set up Asterisk.

[johns]

All of those things are very easy to implement with Twilio (which I thought even before I started working there).