<b>Q: How does a network decide my lead is a 'duplicate'? The user filled the form twice on purpose.</b>

<b>Q: How does a network decide my lead is a 'duplicate'? The user filled the form twice on purpose.</b>

A: Most rejections you'll see aren't about your traffic being fake — they're about deduplication rules you can't see, and they vary by offer.

Networks dedupe leads to avoid paying twice for the same person. The matching usually runs on one or more of:

— Email or phone, normalized (so JOHN@x.com and john@x.com count as one).
— Device fingerprint plus IP within a time window.
— The advertiser's own customer database — if that person is already a known user, the lead is a 'duplicate' even on their first submit to you.

That last one surprises people. A user who's genuinely new to <i>you</i> can be a long-time customer of the advertiser, and you won't get paid for re-acquiring them.

Dedup windows differ: some offers reject duplicates forever, others only within 24 hours or 30 days. Ask your manager two things: what field does dedup match on, and what's the lookback window? Those two answers explain almost every 'duplicate' rejection.

Short version: 'duplicate' often means the advertiser already knew this person, not that your user double-submitted. Learn the match field and the window.

Still stuck? Drop your case in the comments.