Not a regular url shortener...

It took me couple of weeks to build, but 6 months to consider all possible details and gotchas.

You ask me, why so long? It's just a shortener? The reason is - nobody built a shortener like this. 

It spits out short URLs, like any other shortener, but it leads to an amazon page with products pre-added to the client's cart and injects "amazon associate tag". With such a design, It's possible to link to a bundle of Amazon products.