<b>Nelio A/B Testing vs server-side GTM experiments</b>

<b>Nelio A/B Testing vs server-side GTM experiments</b>

Testing affiliate-button variants without nuking your Core Web Vitals.

<b>Nelio A/B Testing</b> (WP plugin)
Pros:
— Test headlines, CTAs, even whole post variants inside WP
— Heatmaps + native page-builder support
Cons:
— Client-side JS adds render delay and can cause CLS flicker on the variant swap
— Per-pageview pricing scales painfully on traffic-heavy sites

<b>Server-side GTM + bucketing</b>
Pros:
— No flicker, variant decided before paint, CWV stays clean
— Pageview cost is your own server, effectively flat
Cons:
— Real engineering: container, edge logic, stats math you build yourself
— No pretty WP dashboard; you live in BigQuery/GA4

<b>For:</b> Nelio if you're non-technical and testing copy on a content site. Server-side if you have dev resources and traffic where flicker/cost actually hurt.

<b>Gotcha nobody mentions:</b> Most affiliate A/B 'wins' are noise. At 2% CTR you need thousands of clicks per variant for significance; people call it at 200 and ship a coin flip.

<b>Bottom line:</b> Easy + small → Nelio. Serious + technical → server-side. Either way, respect sample size.