How do I access the Scratch API?

I tried typing and evven other Scratch API urls into both the primitve URL block and the Web access library URL blocks. Nothing is working. It only returns nothing. I want to make a project that the user can browse through Scratch as if it was a third-party app using the Scratch API. Is there any problem with any part? My internet? The destination? Snap!'s fault? Please help me.

Also, do I need to get a CORS proxy? I don't know how or what it works like.

From what I know, it only loads whitelisted content.

Thats not true

This is due to the CORS policy. You'd need a CORS proxy in order to get data from the scratch api.

I like to use for this purpose.