WordPress to headless: +42% mobile conversion.
A retail brand with a 1,800-SKU WooCommerce catalog had a 5.8s mobile LCP. We migrated it to headless Next.js in 9 weeks.
Problem.
WooCommerce with 14 plugins, mobile LCP of 5.8s, CLS of 0.31 and a 6-step checkout. 73% of traffic was mobile, but mobile conversion was only 38% of desktop conversion. Product landing pages had a 71% bounce rate.
Approach.
Headless architecture with Shopify as the catalog source of truth and Next.js as the frontend on Vercel. URL migration with one-to-one 301 redirects. Checkout reduced to 2 steps (cart -> data + payment + shipping in one screen). Images through next/image with AVIF + lazy loading. Critical CSS inline. Persistent client-side cart with SWR.
Result.
Mobile LCP: 1.6s. CLS: 0.04. Mobile conversion: +42% vs baseline. Organic traffic: +28% in 4 months (same URLs, better Core Web Vitals). Cart abandonment fell from 73% to 51%.