With this, I built a very powerful recipe search engine. It allows you to find recipes using some pretty interesting queries. For example, if the user wants to make 5 recipes that will efficiently use a head of lettuce, 12 bananas, a pound of salmon, and 6 eggs, it can find the most efficient set of recipes that will use as much of those ingredients as possible, while requiring the user to have to buy as few new ingredients as possible. It's also able to normalize the ingredients across all recipes to build really accurate shopping lists. For example, if one recipe calls for 6oz of cheddar cheese and another calls for 1/4 cup shredded cheddar cheese, it knows the weight of 1/4 cup of shredded cheese and can combine that with 6oz. So, pretty interesting technology.
Unfortunately, after several iterations, this completely failed to gain any traction as a consumer product. However, I got dozens of emails from other entrepreneurs who were trying to build similar products and were very interested in the technological side of things. I had a lot of asks if I could share the code, or turn it into a web service.
For this reason, I have decided to re-factor my code as a free, open source project. I'm hoping to find some other developers who could build on what I've done to create the next big recipe startup. The code is all written in C#, but could almost definitely be run under Mono.
It's up at: https://github.com/KitchenPC/core
If you'd like to help contribute, by all means! I really hope it can help someone out!