More and more users using playSMS, and some of them ask about whether or not playSMS provides HTTP API. Well the answer is YES. Its been there quite sometime actually, it is called playSMS Webservices API.
For those PHP developers, you can also try to use PHP class specifically implements playSMS Webservices API. Read about it here: http://antonraharja.com/2014/04/28/playsms-webservices-class/