1. What's needed as a minimum to get the eaternity data (CO2, water usage, animal welfare, rainforest) in our application? There were some kitchen, product & supply endpoints in the API but I'm not sure if they are mandatory or how they should be used. Can we just post to the Recipe endpoint & get the values to then process in our application?

You would need to query our respective end-points for recipes and supplies. That means: send us information about those parts you want the calculations for.

Indeed, you can just use our recipe endpoint, and process the results in your application. For the usage of our recipe endpoint, you would need to consider the following: