How to hire a Python developer: a screening playbook

A practical playbook for startups hiring Python developers: decide which Python role you need, replace the algorithm round with a debugging round, ask production questions, check testing habits and spot red flags. By Witarist, which helps teams hire pre-vetted Python developers: https://witarist.com/hire/python-developers

Transcript

1. How to hire a Python developer A practical screening playbook for startups Witarist · witarist.com/hire/python-developers
2. 1. Decide which Python job it is • Backend & APIs: Django, FastAPI, Flask, Postgres • Data engineering: Spark, Airflow, dbt, Databricks • AI / ML integration: model serving, LLM features, evals • Automation & DevOps tooling • Write down which one is 70% of the role before posting Witarist · Python hiring playbook · witarist.com
3. 2. Replace the algorithm round • Give a small real repo (300-500 lines) • Plant: an N+1 query, a mutable default argument, • and a blocking call inside an async route • Ask them to 'make the slow endpoint fast' • Watch how they read code they did not write Witarist · Python hiring playbook · witarist.com
4. 3. Ask production questions • A Celery task that went wrong: how did you find out? • When would you NOT use async in Python? • Poetry, uv or pip-tools, and why? • A pandas job that fails at 20 GB: what first? • Typing an untyped codebase without stopping features Witarist · Python hiring playbook · witarist.com
5. 4. Check how they test • Fixtures instead of copy-pasted setup • parametrize for edge cases • Can explain mocking the network vs the database • Small, reviewable pull requests Witarist · Python hiring playbook · witarist.com
6. 5. Red flags • Cannot explain the GIL in plain words • 'I would use a library' with no idea how it works • Never read a library traceback • Argues with the reviewer, not the reasoning Witarist · Python hiring playbook · witarist.com
7. Need Python developers this month? Pre-vetted Python engineers, shortlist in 48 hours witarist.com/hire/python-developers