<b>Framework: Deduplication windows — pick the right horizon per metric</b>

<b>Framework: Deduplication windows — pick the right horizon per metric</b>
Dedup removes repeat clicks from one user, but the window length depends on what you're protecting.

— Click dedup: 1-hour window per IP+user-agent. Stops double-fires and rapid refreshes.
— Conversion dedup: 24-hour window per click ID. Stops one sale counting twice across postback retries.
— Lead dedup: 30-day window per normalized email/phone. Stops the same lead being resold.
— Cap-counting dedup: same 1-hour window as clicks, so a refresher doesn't burn an advertiser cap.

Step: store a hash of (IP + UA + offer) with a timestamp; reject matches inside the window for that metric.

Normalize emails (lowercase, strip dots in gmail) before hashing leads.

Review window lengths quarterly; tighten if advertisers flag duplicate complaints.