Defer Ad JS Past First Input, Not Just Load

Defer Ad JS Past First Input, Not Just Load

Heavy ad scripts (Prebid + wrappers + analytics) block the main thread and wreck INP/responsiveness — which now feeds Core Web Vitals and your organic RPM.

What it does — loads the ad stack on first user interaction or after a short idle, not on DOMContentLoaded.
Setup effort (3/5) — gate the wrapper init behind a 'once' interaction listener + idle fallback timer (~3s safety net).
RPM lift seen — +4-8% RPM, almost entirely from INP improving and lifting organic sessions; direct ad revenue is flat-to-slightly-down.

Pros — big responsiveness win, better CWV, smoother scroll.
Cons — first ad fires later, costing a few impressions on instant-bounce users; needs the idle fallback or scrapers/no-interaction users see no ads.

Lift: ★★★★☆ — Risk: ★★☆☆☆
Best for: script-heavy stacks with poor INP. Skip if your INP is already green — the gain's already banked.