Is it possible to simulate a user on a site of any complexity?

Question

Python

Are there any restrictions that may prevent you from creating a bot that works on some site?
I know that on some sites it is possible to emit a user using HTTP requests. But there are sites on which this no longer works. What is used then?

Answer 1

For example, they use browser emulators, the script does everything the same as the browser, but without the GUI. The most popular tool for this is Selenium