Prebid timeout: 1000ms vs 1500ms vs 3000ms

Prebid timeout: 1000ms vs 1500ms vs 3000ms

Benchmark drop. Bid responses captured by timeout window (n=140 sites):

— 1000ms ▮▮▮▮▮▮ 71% of bids arrive
— 1500ms ▮▮▮▮▮▮▮▮ 89%
— 3000ms ▮▮▮▮▮▮▮▮▮ 96%

Looks like 3000ms wins. It doesn't. The marginal 7% of bids arriving between 1500-3000ms carry below-median CPM (cost per mille — what advertiser pays per 1000 impressions) and your viewability craters because the ad paints after the user scrolls past.

Net revenue peaks near 1500ms on mobile, 1800-2000ms on desktop. Setting failsafe timeout 500ms above auction timeout prevents blank slots.

So what: Dropping 3000ms→1500ms lifted viewable RPM ▲ 6.8%, total bids ▼ 7%.