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 providers who have decades of domain expertise creating professional-grade data for sale. Thanks to this expertise, premium data feeds 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 data feeds on Quandl. You can find a list of our premium data feeds on our partners 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 data feed 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 data feeds here. Check off "free" to the left to view free data feeds only.