iOS cache folder?

My PC application turned into a iOS app, needed to run on a closed enterprise app-store on equal hardware (iPad Pros).
It’s some kind of material/paint configurator which is based on a json description file and then locally caching all textures from the web (thousands), loaded per material on demand on runtime. Textures should update from the web as needed.

1. how do I cache files locally on ios? is there some persistent cache folder accessible? How can I download and put files into it?
2. how do I get the content of a json file locally or from an URL as string into Unreal? Parsing the json string is possible on many ways, I’ve managed that.

  1. You can try this How can I write to text files? - UE4 AnswerHub
  2. there is a http library and a Json parsing library built into unreal engine see How to make an HTTP Request from Unreal - General Discussion - Unreal Engine Forums