VoicePHP and Tropo - first impressions

In a previous post, I discussed a number of issues regarding the scripting approach taken by a number of new telephony platforms. But my opinions were somewhat uninformed, as they were based solely on the provided documentation and not on real experience with those platforms.

So I decided to try two of them: VoicePHP and Tropo. Here are my first impressions. (These are not necessarily profound thoughts, since I played with both platforms for a few hours each.)

VoicePHP

VoicePHP is a voice platform provided by TringMe, an Indian company. To use it you have to register for a 7 day beta period.

As its name implies, voice applications are written in PHP. You configure the script URL in your TringMe account and call the application. You have to host your scripts on your own web server.

To call the application, TringMe offers several choices:

• Call a provided phone number in the US. (I reside in Canada, so it's a no go for me. I don't want to make long distance calls just to test small script changes.)
• Call using a standard SIP phone. That's what I did. Works quite well.
• Call the application using a Flash-based widget on a web page. That's really cool. Makes it very easy to develop a voice application and make it available to a large audience.
  

I tried to implement a small sample application making use of voice recognition. VoicePHP is supposed to support ABNF grammars. Unfortunately, all I got were "no match" events (or were they?). So I didn't get very far. Since there is no debugger or log files I can inspect, I quickly abandoned without knowing whether the fault was mine or not. The platform may be great for DTMF applications, but support for speech recognition did not convince me. And documentation is very light.

At least, their support team was quick at answering my questions. So I'm sure VoicePHP will get better over time. But for now, they did not convince me that the approach is superior to VoiceXML.

Tropo

Tropo is a voice platform in the cloud, provided by Voxeo, a Florida-based company. It's kind of a GoogleApp Engine for voice applications. It offers support for five scripting languages: PHP, Python, Ruby, JavaScript, and Groovy. Your applications can be hosted on their servers or you can serve them from your own web/application server.

You can add any number of applications to your account. Each application is assigned a separate Skype/SIP/INum phone number. As there is a local number for INum in Montreal, I can easily test my applications using either the PSTN or a SIP phone. Both for free.

To test the platform, I implemented a simple application that tells me the status of the web sites I maintain (I get SMS messages once in a while from a ping-like program telling me that one of my applications is down, but its usually due to unusual latency in the network. When this happens, I want a quick way to check if the web application is up and running.) The application asks me for the name of one of my web sites using speech recognition, and fetches the main page of the selected site. If the status code is 200, it tells me that the site is up and running, otherwise it tells me that the site is down. (I'll show you the code in my next post.)

I implemented the application in JavaScript, since it is the language among the supported ones I know best. Tropo uses Rhino, the Mozilla Java-based ECMAScript interpreter underneath, with support for E4X (ECMAScript for XML, an extension to ECMAScript that adds native support for XML).

In contrast to VoicePHP, Tropo provides a good web-based debugger and log viewer. That's an essential part of any development environment. It makes it easy to spot bugs and problems in your application. (I have not been able to stop the execution of an application, as advertised, though. But I have not contacted their support team yet to get help on this issue.)

Speech recognition works great, but my main complain is that the syntax for grammars is quite limited when you're used to developing grammars in ABNF or GrXML format. You cannot ask for dates or numbers, for example. Once they support those formats, sites like NuGram Hosted Server (shameless plug) will become usable to make great mashups with robust dynamic grammars. (I already have a working JavaScript API to generate dynamic grammars using NuGram Hosted Server that I have tested on Tropo. It's just that Tropo cannot use the generated grammars yet.)

Overall, developing a small application on Tropo was really fun!

Conclusion

Although both platforms are quite promising, I found Tropo to be much more mature than VoicePHP. Their website is well designed, effective, without too many bell and whistles. And they provide the right balance of features and tools to help test and debug applications.

So these were very first impressions on VoicePHP and Tropo. I know there are lot of issues I did not mention. I may address them in future posts.

So what is your experience with these platforms? Please share your thoughts in the comments below!

[Disclaimer: although Voxeo owns VoiceObjects, a Nu Echo partner, I based this very informal review solely on my experience using both platforms for a couple of hours each.]