Quandl API offers a uniform, simple, RESTful interface which is used in search engine for found out the numerical data.Quandl APIs are used in several million financial, economic and social datasets. Quandl are provide many indexes data from multiple sources allowing users to find and download in various formats with the help of Quandl API and these APIs access is possible through packages for multiple programming languages including R, Python, Matlab and Stata and an Excel add-in allows access to data, including stock price information. In Quandl API sources include the UN, Worldbank, Eurostat and several hundred more and is free to use. All open databases have unrestricted permissions. To access any premium database, you must be a subscriber to that database.