Ad click event aggregation

Ingest tens of thousands of ad clicks per second, deduplicate retries and fraudulent double-clicks, and produce per-minute billing and dashboard counts within seconds. Because clicks are money, the pipeline needs event-time windowing, watermarks for late mobile events, and end-to-end exactly-once accounting.

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Duration 45:00

Requirements checklist

Record every ad click event (`clickId`, `impressionId`, `adId`, `campaignId`, `eventTime`, user context) and redirect the user to the landing page with minimal delay.Aggregate click counts and spend per `adId` and `campaignId` in 1-minute tumbling windows for live advertiser dashboards and budget pacing.Deduplicate repeated clicks carrying the same `clickId` / `impressionId` and filter invalid or unserved impressions.Click redirect latency under ~50 ms p99; dashboard freshness within ~10–30 seconds.No double-billing when clients retry or stream workers crash and replay a partition.Zero lost clicks once accepted by the collector (durable partitioned log + raw archive for offline reconciliation).

Clarifying questions

Are we only counting clicks, or joining clicks against ad impressions to verify attribution and compute CTR?
How fresh do advertiser dashboards and budget-pacing decisions need to be (seconds vs minutes)?
How late can offline mobile click events arrive, and how should late events affect already-closed minute buckets?
What is the peak click rate, and can a single viral campaign dominate traffic?

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requirements

Suggested time: about 6 minutes. Covers late mobile events, impression-to-click attribution, and budget pacing.

Notes for requirements