The Netflix Senior Bar-Raiser Set
Six Python questions that map to the bar-raiser part of a senior streaming-platform loop. The set rewards depth over speed: each prompt has a follow-up about failure modes, observability, or rollout.
Question Bundle
Python
interview-prep
netflix
bar-raiser
distributed-systems
By @arjunrivera
December 4, 2025
·
Updated May 20, 2026
745 views
15
4.4 (14)
Write map_concurrent(items, fn, *, concurrency=10) that runs an async fn over items with a bounded parallelism. The bar-raiser question: what breaks if you skip the semaphore?
Walkthrough
Python
await map_concurrent([url1, url2, ..., url100], fetch_json, concurrency=10)
# At most 10 in-flight fetches at any moment; returns 100 results in input order.
# Without the semaphore: all 100 fetches start at once -> connection pool exhaustion
# and the downstream sees a thundering herd.5 more questions and all solutions are locked.
Purchase this item to access all questions, code snippets, and solutions.