Python LLD interview questions – staged machine coding practice

Practice low-level design interviews in Python, right in your browser. Each problem runs like a real machine coding round: pass the visible tests, then the interviewer extends the requirements across three stages. Hidden tests attack the core invariant of every design. Free, no signup.

LLD problems

• Parking Lot LLD Interview Question - Python Machine Coding Practice - Solve the Parking Lot low-level design interview question in Python, in your browser. Staged like a real machine coding round: pass the basics, then the interviewer extends the requirements.
• Rate Limiter LLD Interview Question - Python Machine Coding Practice - Design a rate limiter in Python, in your browser: token bucket, per-user and per-endpoint limits, then sliding windows. Staged like a real machine coding round with hidden tests that attack the limit invariant.
• Splitwise LLD Interview Question - Python Machine Coding Practice - Design Splitwise in Python, in your browser: equal, exact and percentage splits, then simplify-debts settlement. Staged like a real machine coding round - balances must always sum to zero.
• LRU Cache with TTL LLD Interview Question - Python Machine Coding Practice - Design an LRU cache in Python, in your browser: classic eviction, TTL expiry on logical time, then weighted entries. Staged like a real machine coding round with hidden tests on capacity and eviction order.
• Notification System LLD Interview Question - Python Machine Coding Practice - Design a notification system in Python, in your browser: channels, user subscriptions, then retries with backoff and rate limits. Staged like a real machine coding round - deliver exactly once, record every failure.