Hi… Their docs site is back up now, at least, although it’s missing some pages that used to be there. It does still feature a large section on the sprites CLI, though, which was invisible for a while:
https://docs.sprites.dev/cli/commands/
This one is coming soon, according to an HN post, and it was said then that there’s already an API that works for such transfers.
This is also planned, but maybe not arriving as quickly. (Apparently, there are internal debates about what exactly the commands are and how ambitious they get.)
Hope this helps a little!