How can I trust Quandl's data?
Quandl has two types of data: premium data and free data.
Quandl's premium data is curated by specialist data vendors who have decades of domain expertise creating professional-grade data for sale. Thanks to this expertise, premium databases are without exception more accurate, better documented, better structured and timelier than their free equivalents. We vouch for the quality, reliability and value of all premium databases on Quandl. You can find a list of our premium databases on our vendors page.
Quandl's free data comes from established sources such as central banks, multinational organizations, government agencies, stock markets and commodity exchanges. Every single free dataset on Quandl has a fully transparent link back to its source. This means you can always verify the data as published by its original source. Transparency is the ultimate enabler of trust. You can browse/search our free databases here. Check off "free" to the left to view free databases only.