Quandl

Quandl is a portal to numerical data (especially time-series data) that is stored on the internet. It allows users to search over 5,000,000 financial, economic, and social datasets. Once found, data can be downloaded, visualized, saved, shared, authenticated, validated, uploaded, indexed, merged, and transformed. Every dataset on Quandl is available through its REST API, regardless of where, how, or in what format the data was originally published.