The Flowroute Messaging PHP SDK by Flowroute offers integration with a VoIP and messaging platform designed for PHP applications. This SDK supports the v2 APIs from Flowroute that provides outbound SMS with its Messaging API. It requires PHP 5.4.0+.
The Nexmo SMS API is a service that allows you to send and receive SMS messages anywhere in the world. Nexmo provides REST APIs, but it's easier to use their official Java SDK. This tutorial covers how to send and receive SMS messages with the SDK so that you can use them in your applications.
Ask Ziggy, best known as the "Siri for Window's Phone," has launched the Ask Ziggy API, which enables natural speech processing within any app. The API enables speech processing, but must be used in conjunction with other speech services to complete the offering (e.g. Nuance, AT&T, etc.). Ask Ziggy expects the API to be used primarily for enhanced in-app search features; however, the opportunities extend much further than basic search.