Walk into the interview already prepared.

Fresher (0–3 years): Junior Python Developer

1. List vs tuple vs set vs dict: when do you use each?
2. Explain *args and **kwargs.
3. How do you handle errors in Python?
4. Which Python type is immutable?
5. What does [x * 2 for x in range(3)] produce?
6. Fastest way to check whether an item exists in a large collection?
7. What does "with open(path) as f:" guarantee?
8. Which tool isolates a project's dependencies?
9. What is the result of 7 // 2?

Mid-level (3–8 years): Python Developer

1. Explain how you would structure a medium-size Python service.
2. When would you use threads, multiprocessing or asyncio?
3. How do you find and fix a performance problem in Python code?
4. What does a generator (yield) give you?
5. The GIL in CPython mainly limits…
6. What does @property do?
7. Which framework is common for testing in Python?
8. asyncio is best for…
9. A default mutable argument (def f(x=[])) causes…

Experienced (8–15 years): Senior Python Engineer

1. How would you set Python engineering standards for a team?
2. Design a plugin system in Python.
3. Scale a Python data-processing job that has become too slow.
4. Type hints with mypy mainly help…
5. Dependency injection in Python helps…
6. Memory leaks in long-running Python services often come from…
7. Best practice for releasing internal Python libraries?
8. Choosing between pandas and Polars for big data frames, Polars offers…
9. Securing a Python web API includes…