InvisibleHand is a browser add-on that automatically informs users when the product that they're shopping for is available at a lower price elsewhere. It also provides a link to the lowest-priced option. InvisibleHand can circumvent Minimum Advertised Prices (MAPs) in the U.S. by uncovering the real prices of products in cases where the price is too low to legally advertise.
The InvisibleHand API allows users to access the real-time prices for millions of products at hundreds of retailers. It is also capable of discovering where else a product is sold and retrieving product identifiers, such as UPCs, EANs, MPNs, ASINs and ISBNs.