Django

Does Django provide object-level permissions by default, and how should you enforce them?

Clarifies Django's object-permission hook and enforces ownership or tenancy in the query and policy path.

Does saving a Django model validate it?

Distinguishes Django model saving, explicit model validation, form validation, and database constraints.

Fix a Django N+1 query and protect it with a query-count test

Repairs a Django serialization path with select_related and prefetch_related, then locks the query shape with a regression test.

How do Django atomic blocks, savepoints, and on_commit callbacks work together?

Defines Django transaction nesting, exception boundaries, and post-commit work without promising durability.

How do Django authentication backends authenticate users and resolve permissions?

Explains backend ordering, session affinity, permission aggregation, and the difference between identity and authorization.

How do Django session authentication and CSRF protection work together?

Connects browser-sent session cookies to Django's CSRF token checks for unsafe requests.

Python Backend

Python backend interview preparation grounded in real service development.

A backend-focused Python preparation path covering language semantics, typing, FastAPI, Django, concurrency, data access, testing, security, background work, reliability, and production diagnosis.