The Instapaper team, writing on the company blog:
Since the launch of our new parser in January, we’ve gotten lots of inquiries from developers about using our parser for third-party applications. With the new Instaparser API, app developers can use our parsing tools to provide users with a lightning-fast browsing experience optimized for mobile devices. Data scientists can use the tools to normalize input for text analysis. And hackers can do, well, whatever hackers might like to do with lightning-fast access to clean, standardized web page data.
The addition of an API makes sense to me – now third-party developers (think Twitter clients or news readers) can access the same powerful parser that Instapaper uses (which is excellent). I'm curious to see which iOS apps will implement it in the near future.
There's also a free tier available here.