Tell me about a Django project you have worked on. What was your role and what was the hardest part?

Note: Interviewers are trying to work out whether you have shipped Django or only followed a tutorial. Details about deployment, migrations, and data volume are what separate the two.

Structure it in four parts:

• What the application did, and its scale. Number of users, size of the largest table, request volume at peak. One line is enough, but the numbers matter.
• Your actual scope. Whether you owned models and migrations, the API layer, background tasks with Celery, or the deployment. Be precise — inflating this is easy to catch with a follow-up question.
• The genuinely hard problem. Strong candidates: a migration on a large table that could not lock it, N+1 queries discovered under load, a permissions model that grew beyond what Django's built-in system handled, or moving slow work into a task queue.
• The outcome and what you would redo.