Built the e-commerce frontend for POC Sports, a Swedish performance sports brand, from first commit to production. Headless architecture serving static pages across four global markets.

1,609 commits · 25 locale × currency combinations · 4 markets

Statically serving e-commerce across four markets

Most e-commerce sites are fully dynamic. POC Sports needed 25 locale and currency combinations with fast page loads on every continent, while keeping cart, checkout, and pricing dynamic per session.

What I built

• Custom Centra API client with dual modes: token-less STATIC for build-time and sitemaps, session-based DYNAMIC for user-facing pages. Curried methods (method(config)(params)) made market config reusable everywhere.

• Multi-market static generation: pages pre-rendered per locale with force-static and 6-hour ISR. One build covers all 25 combinations.

• Edge middleware that creates a Centra session on first visit, detects market, language, and currency via IP geolocation, and sets the session cookie. It is the boundary between the static and dynamic layers.

• Content layer: Sanity CMS with live preview and portable text, integrated into Server Components.

How it's built

Request → Edge Middleware (session + locale detection)
       → Static page from CDN (force-static, ISR)
       → Sanity CDN for content | Centra DYNAMIC for products
       → Zustand (UI state) + React Query (server state)

Product pages fetch fresh on every request: pricing and stock must be real-time. A Result<T, E> type with ts-pattern enforces exhaustive error handling at every API boundary.

Decisions

• ISR over full SSR: CDN-speed pages at the cost of 6-hour staleness. For a catalog that changes weekly, that is fine. QA uses revalidate: 0 so merchandisers see changes instantly.

• One dual-mode client over two separate clients: the CheckoutApiHeader service detects context and sets the right auth headers. Consumers do not need to know which mode they are in.

Hard part: caching without serving stale prices

Static pages are fast, but a cached page showing the wrong price in the wrong currency is not ideal.

The solution split the problem into layers. Content caches via Sanity's CDN. Product data (price, stock) fetches fresh per-request using the session token, which carries market and pricelist. Metadata uses 24-hour ISR. A stale meta description never costs a sale. The middleware is the gatekeeper: it runs on every request, establishes the session, and writes market context into a cookie that downstream pages read.

What I'd do differently

On-demand ISR via webhook instead of time-based revalidation. A Sanity webhook triggering revalidateTag would give instant content updates with zero unnecessary cache misses. Six hours was a safe guess, not an optimal answer.

Today

The site is live at poc.com.