News

Windows Azure Devs Get Telephony and Text Messaging APIs

Twilio's APIs let developers build the ability to initiate and receive phone calls from mobile and Web apps.

• By Jeffrey Schwartz
• May 4, 2012

On Wednesday Microsoft announced that it has signed a deal with Twilio that will give developers the ability to have voice and SMS-enabled applications run on the Windows Azure cloud service.

San Francisco-based Twilio offers a cloud-based telephony service. Through its APIs, developers can initiate and receive phone calls from mobile and Web apps. In addition to call control, the APIs let app developers integrate voice messaging, interactive voice response and text messaging.

The partnership is targeted at developers looking to build apps that allow users to initiate and receive phone calls from their apps. It will also appeal to those looking to build that capability into mobile and Web-based customer relationship management (CRM) apps, as well as interactive voice response and distribution of apps to mobile devices via text message rather than through app stores, Plax said. The API simplifies access to telecom networks, he added.

"Our mission is to unlock the black box of telecommunications by building a simple, clean abstraction layer on top of the complex and esoteric telecommunications protocols," said Jon Plax, Twilio's director of product management, in an interview. "We present simple RESTful APIs, that can be used from any language, any platform, that require a very basic developer skill set to utilize. You don't have to be a telecom wonk in order to build applications that do interactive voice communications or interactive SMS."

Twilio's APIs will work with applications built in Java, .NET and PHP running on Windows Azure. "Sending text messages from Windows Azure has never been so easy," wrote Brian Goldfarb, director of product marketing for Microsoft's Windows Azure group, in a blog post.

The company is offering Windows Azure developers 1,000 free text messages or 1,000 voice minutes to try the service, which costs 1 cent per minute per inbound call or per message and 2 cents per outbound call and $1 per month to host a telephone number. Twilio doesn't require contracts -- users pay just for what they use, Plax said.

Twilio's client libraries, which allow developers to build audio into their Web and mobile apps, support Javascript, iOS and Andoid. The libraries enable call control routed through the Twilio service, which is hosted on Amazon Web Services Elastic Compute Cloud (EC2). Asked if Twilio was considering running any of its service in Windows Azure, Plax said no such discussions have taken place.