Design a user behavior monitoring system

## System Design: User Behavior Monitoring System You are asked to design a monitoring/analytics system that collects **user behavior events** from clients (e.g., **app install**, **user clicks**, etc.). The system must support: ### Functional requirements 1. **Real-time monitoring**: show near-real-time metrics on dashboards (e.g., installs per minute, click-through rate). 2. **Raw event retention**: store **raw events** for large **offline/batch jobs** (e.g., daily/weekly aggregation, deeper analysis). 3. **Metric discovery/confirmation**: you should clarify with the interviewer which exact product metrics are needed (assume multiple counters/ratios, grouped by dimensions like platform/app version/country). ### Non-functional requirements (assume typical expectations) - Handle **high write throughput** (many clients emitting events). - **Low-latency** updates for dashboards (seconds-level is acceptable unless otherwise specified). - **Scalable** storage and compute. - **Reasonable correctness** for aggregates (be explicit about tradeoffs: at-least-once vs exactly-once, late events). ### Out of scope - System/infra observability metrics like host reliability/latency are **not required** unless you want to briefly mention them. Design the architecture, key components, data flow, storage choices, and how you compute/serve real-time metrics vs offline analytics.