You will need to run a workflow everyday to generate and save this JSON. You can build a backend workflow to do it and, in the ends, reschedule itself to today + 24 hours.
How to generate the JSON
You can use a plugin or generate your JSON ustin the command : formatted as text.
Take a lok here:
How to save the JSON;
What are you planning here? Download, send by e-mail or use a cloud service?