When I visited scratch-www, it said I need to create my own Scratch API server as following:

scratch-www wrote:

…create your own backend systems to perform those functions.

So I searched the web for one that is already created, but I found none.

Why is there no shared scratch api clone? Isn't it allowed to share one?
I would really like to share my own when it's done. (probably it won't be completed forever)

Yes, if you manage to recreate Scratch's back-end code, you would be allowed to share that.

The reason that there are no public recreations of Scratch's API is because nobody has shared one yet.

Thanks! That really makes sense.

i've completed account authentication module!