DTC commerce migration

Three-week audit of the existing Shopify Plus stack: theme bloat, third-party tag inventory, image weight, render-blocking JS, hydration cost, and the full SEO surface (URLs, schema, sitemaps, indexation, backlinks). We left the audit with a ranked list of every regression risk and every performance win, sized in milliseconds.

Built a headless Next.js 16 storefront against the Shopify Storefront API. Product, collection, and cart routes are statically generated where possible, streamed where dynamic, and use Next.js Cache Components so PDPs render fast and stay fresh. Checkout stays on Shopify so we do not rebuild the part that already works.

Every legacy URL mapped 1:1 to the new architecture in a single CSV. Product schema, collection schema, breadcrumb schema, Organization, and WebSite schema all rebuilt server-side from typed data. Sitemaps regenerated, GSC and BWT both validated pre-cutover.

We set hard budgets: LCP ceiling 1.8s mid-tier mobile, INP ceiling 150ms, JS payload ceiling 120KB gz on home and PDP. Lighthouse CI ran on every PR and blocked merges that breached. The discipline is mostly cultural, but the gate makes it real.

Launched behind a feature flag, promoted by route group over 24 hours with live rank and conversion monitoring. We held the cutover twice for unrelated tag-manager issues and resumed once cleared. Final cutover completed inside the planned window.

Daily CWV monitoring via web-vitals plus Vercel Analytics RUM, weekly rank diff against baseline, weekly conversion comparison, and a single Slack channel for any anomaly. The conversion lift held through the first full month and into quarter two.