- [x] how compatible are JSON, XML, and CSV? - [x] what (controller) presenter libraries are a good fit for us, using Rails and (maybe) Grape. - [x] check categories on Ruby Toolbox (https://www.ruby-toolbox.com/categories/API_Builders) - [x] especially take a look at [Grape](https://www.ruby-toolbox.com/projects/grape), [Representable](https://www.ruby-toolbox.com/projects/representable), and [Rabl](https://www.ruby-toolbox.com/projects/rabl). - [x] Clarify with Paggy, if JSON, XML, and CSV should really be the same (schema).