What is glitch backend architecture? How are they able to do all that?

I want to know what is glitch backend architecture, technologies they use and how they protect their server from suspicious codes?

Also in FAQ they mentioned that every project is in a container, what is the containers exactly?

This is out of date and the specific technologies and architecture have changed, but it’ll give you an idea of the general approach: https://blog.fogcreek.com/hyperdev-tech-stack/