Client — global media company (tech news), 50K+ articles, 12 localized editions. Monolithic WordPress — TTFB 2.8s, editor lock-in, front-end team blocked. Needed decoupled CMS + fast global delivery without retraining 40 editors. Scope: headless WP (content API) + Next.js frontend, ISR/SSG hybrid, edge CDN, preview mode for editors, SEO parity (hreflang, schema, sitemaps). Implementation: • WP: custom post types, ACF, REST + WPGraphQL, webhook on publish → revalidate; • Next.js 14 App Router: ISR (revalidate 3600), on-demand revalidation API; • i18n: 12 locales, hreflang, locale-specific sitemaps; • CDN: Cloudflare/Vercel edge, image optimization (AVIF/WebP), LCP budget < 2.5s; • preview: draft tokens, secure preview URLs for editorial workflow; • migration: 50K posts scripted import, redirect map 301 (legacy URLs preserved); • search: Algolia index sync on publish; • CI: visual regression, Lighthouse CI gate (score ≥ 90). Stack: WordPress, Next.js, TypeScript, GraphQL, Algolia, Cloudflare, Node.js. Acceptance: TTFB p75 < 400ms, 0 SEO traffic drop 90 days post-cutover. Result: Core Web Vitals green; organic traffic +18% in 6 months. NDA: brand not disclosed.