[aGHz]

You could simply encode the json to base64 and put it in the url fragment (hash). Then you can save by bookmarking the url and share by copy/pasting it, all without a server. I've seen some web games use this method but I can't remember which off the top of my head.

[bbkane]

The Vega Lite plugin does this: https://vega.github.io/editor/#/custom/vega-lite

I think Google maps does this for manual bike routes too?