Application algorithm for working with the gist library (gists)?

Question

API

I want to make web applications for easy viewing, adding and grouping gists. In fact, a copy of GistBox.

However, I can’t understand what technologies to use and what algorithm for the operation of this all? Questions:
1) When downloading the application and when navigating through categories, pull the gists using the github API every time? Or do I need to use an intermediate base? If so, how to synchronize correctly, given that gists can be added both through the application and through the github itself?
2) How to group histists? There are no categories for gists on the github, but the application needs it.
3) Can the application be implemented as a SPA?
4) What technologies would you use?