When I'm deciding which intergalactic data set to work with, I don't want to take any half measures. That's why I'm drawn to the Sloan Digital Sky Survey (SDSS). In their own words, "The Sloan Digital Sky Survey (SDSS) is one of the most ambitious and influential surveys in the history of astronomy." Sounds like their putting the project right up there with the greats like Galileo. You can bring this level of astronomical greatness into your app via the SDSS APIs: SDSS cone search & SDSS image cut-out.
DataDryad.org constitutes a general purpose repository of the data underlying scientific publications. DataDryad’s entire repository is discoverable through the Dryad DataONE API. The scientific and medical data of which the database is composed includes tables, spreadsheets, flatfiles, and more from peer-reviewed published papers.
Have you ever heard of a Chief Science Officer? I recently spoke to Kontagent’s CSO and was excited to learn that Kontagent’s world of big data processing is one of the few places in the world in which academic exercise is directly applicable to industry. Kontagent is a user analytics platform which can easily be integrated into any web site or mobile app. The ease of integration results from the decision to provide a RESTful Kontagent API.