[lolpanda]

Those mini apps are built on the same web stack. I believe the main advantages of creating mini apps are that the platform provides identity (allowing you to know who the users are upon permission approval) and payment APIs.

[paradite]

They use a mixture of web rendering stack and native rendering stack. See my other comment.

There are also more architectural diagrams thst illustrate the layers in the links I posted in my original comment.

[aquariusDue]

I believe Telegram has something similar too.