PrestaShop Core Web Vitals Optimization

Core Web Vitals (CWV) are Google's 3 performance metrics: LCP (Largest Contentful Paint, < 2.5s = good), INP (Interaction to Next Paint, < 200ms = good, replaced FID in 2024), CLS (Cumulative Layout Shift, < 0.1 = good). Since 2021 these metrics are part of Google's ranking algorithm. A shop in "poor" on any of the 3 is systematically demoted on mobile vs competitors in "good". The impact is measured in lost positions and mobile conversion.

Depends on your starting point. On a poorly optimized shop (LCP at 5s, Lighthouse score 30/100): we typically achieve LCP < 2s and 80+/100 score within 2-4 weeks of work. On a decent shop (LCP at 3s, score 60/100): we reach "good" on all 3 metrics within 1-2 weeks. Gains aren't magic: they're reproducible results based on concrete tactics (critical CSS, preload, lazy loading, TTFB).

Audit + costed action plan: from €2,500 (5 days, PDF deliverable + priority recommendations). Audit + priority fixes: from €4,500 (audit + 5-10 days of fixes on the top 3 optimizations). Complete optimization (audit + all fixes on all axes): from €8,000. The quote specifies the fixes included based on your shop.

5 main axes: (1) LCP — critical CSS generation for homepage and categories, hero image preload, server TTFB optimization (cache, OPcache, compression), proper lazy loading of below-the-fold images; (2) INP — third-party JS audit, removal of parasitic trackers, defer / async of non-critical scripts, event handler optimization; (3) CLS — image space reservation (width/height), font-display swap + preload, banner reservations; (4) TTFB — cache, FastCGI, OPcache, query optimization; (5) JS bundling — modulepreload, tree-shaking, removal of unused libraries.

Very little, if done correctly. Critical CSS is extracted without touching the theme. Preload happens via a meta in the head. Lazy loading uses native HTML5 attributes. TTFB is improved server-side (PHP cache, MySQL) without touching design. Visual rendering remains identical — you gain in performance without changing appearance.

Yes, frequently. We optimize third-party modules via: (1) conditional lazy loading (don't load the slider on checkout pages); (2) deferred loading (load after 3s of inactivity); (3) removal of unused assets; (4) replacement with lighter alternatives. If a module remains a blocker, we flag the issue in the report and list potential alternatives.

Cumulative, it's a snowball effect: (1) mobile SEO goes to good, you climb 3-10 positions on competitive keywords (depending on sector); (2) mobile conversion rate increases by 5-25% (users no longer abandon during loading); (3) bounce rate drops by 10-30%; (4) since LCP is also a trust signal, ad CPC improves (Google Ads Quality Score). For most shops, the investment pays back within a few months.

Follow-up included for 30 days post-go-live: daily CWV monitoring via PageSpeed Insights API and CrUX (Chrome User Experience Report), weekly metrics report over 30 days, adjustments if some pages stay in orange zone. After these 30 days, option to continue in maintenance (see PrestaShop Maintenance) with CWV monitoring included.