System designHardsd-g266

Subject Event streamingLevel Senior–Staff~50 minCommon in Distributed systems interviewsIndustries Technology

Question

Design an ingestion pipeline for 50 million IoT devices (smart meters, EV chargers, sensors) each emitting a small telemetry record every 10 seconds — ~5M writes/sec at peak, bursty when a firmware rollout reboots a region simultaneously. Records must be durably stored, queryable as time series, and trigger near-real-time alerts (e.g., over-temperature). Devices have weak/intermittent connectivity and limited buffering. How do you handle the massive fan-in without dropping data or melting the backend?

What a strong answer looks like

Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts — data model, bottlenecks, consistency, failure modes — and name the trade-offs you are making.

Learn the concepts

Narrate your design

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Run or narrate your approach, then ask the coach.