Issuu, the Danish startup battling the likes of Docstoc and Scribd in the professional document publication and sharing space, is today introducing a REST-based API that enables its users to automatically upload and manage publications, bookmarks, and folders under their accounts.

That means developers and designers can henceforth tap into the Issuu platform and services to equip their own applications and websites with the oft-needed functionality of offering document consultation without the need for end users to download the docs or to visit the Issuu website. Issuu already offered two APIs: one for Search (which allows developers to sift through all Issuu publications, comments, and users) and one for its Viewer product. It is now adding a third one for the ‘Upload’ feature, obviously an essential one.

When Docstoc recently left the beta phase, it also launched with a number of open APIs. I’d check up on Scribd too, but their website is currently down.

Either way, we like Issuu here at TechCrunch. When the company first launched, it was one of the first services of its kind whose interface and functionality didn’t suck. The startup has been busy adding new features to its products and venture capital to its bank account – it raised a total of $6.25 million in funding to date – and is seeing decent traction as well.

According to co-founder Martin Ferro-Thomsen, Issuu currently services over 325 million monthly unique page views across its entire network of publishers (including embeds in articles etc.) and welcomes 4.4 million unique visitors to its main website Issuu.com every month.