If you’ve used Flask, pytest, or Django, you’ve used decorators. @app.route, @pytest.fixture, @login_required — they’re everywhere. But most developers treat them as magic syntax without understanding what’s actually happening. Once you do understand them, you’ll start reaching for decorators in your own code. What a decorator actually is A decorator is just a function that takes a function and returns a function. That’s it. def my_decorator(func): def wrapper(): print("before") func() print("after") return wrapper def say_hello(): print("hello") say_hello = my_decorator(say_hello) say_hello() # before # hello # after The @ syntax is shorthand for exactly that reassignment. This: ...