take a look @ https://www.ibm.com/smarterplanet/us/en/ibmwatson/developerc.... There is also doc link once you click on the service you have bounded. There are samples in java and nodejs. (samples coming soon in github)
As far as I can tell, most of the documentation essentially begins, "First, deploy a web app on our platform". Which is fine I guess, but isn't nearly as simple as the HTTP APIs you see from many other recent SaaS providers. As least for me, I'm pretty unlikely to jump through those hoops. Maybe others will be different.
Edit: All the way down on the bottom of the documentation page, past the research references, there's a link to HTTP API documentation--literally the last link on the page.