“Receive status updates anytime, anywhere – a simple API to send instant messages directly from your code” Code name: SignalTrigger. How does it work? SignalTrigger, “lets you send messages from your code to your instant messengers.” Plenty of services are supported, including Whatsapp, Skype, Twitter, VK and Hangouts – and more are being added as we speak.
You can even try it out on the site (see above screenshot) to get the feel for it. You can sign up for free and 100 messages are included absolutely free per month with an upgrade feature for more messages. The service looks great and they also run a nice little blog. Check them out!