Count Visits in One Minute
Company: Ramp
Role: Software Engineer
Category: System Design
Difficulty: hard
Interview Round: Technical Screen
Design a system that can report the number of website visits in the most recent 1-minute sliding window. The website may receive high traffic, and the count should be queryable in near real time.
Discuss:
- what exactly counts as a visit,
- the ingestion and event pipeline,
- how to maintain rolling 60-second counts,
- storage choices,
- scaling, fault tolerance, deduplication, late events, and monitoring.
Overview: This question evaluates a candidate's ability to design scalable, fault-tolerant real-time analytics systems for maintaining a sliding 60-second visitor count, covering competencies in event ingestion pipelines, deduplication, late-event handling, storage selection, scaling, and monitoring.
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