Easiest remote database / datastore to save debug data?

I have this app that works totally offline, everything is done on the client. But now I have some strange error reports from users that I have to debug. To do this I have to remotely save two JSON arrays somewhere where I can then look at it. Connecting it to a “user” or something like that probably won’t be necessary.

What is the easiest remote database / datastore to implement in my app?

It shouldn’t use any native code so I can deploy it without a binary change, so JS only library preferred.