Full-Page Edge Caching for Dynamic Storefronts: The Hard Part Is Not the Caching
Every CDN can cache an image. Caching the rendered product page of a live store - with inventory moving, prices changing, and carts in session - is a categorically harder problem, and it is where the real speed wins live.
Why storefronts resisted caching
Commerce pages look cacheable but are full of per-user and per-minute state: cart counts, inventory badges, personalized recommendations, promotional pricing. Cache too aggressively and shoppers see stale prices or - the catastrophic case - someone else's session data. Cache too conservatively and you have an expensive pass-through. This is why storefront HTML historically bypassed the CDN while assets cached around it.
The working patterns
Modern edge delivery solves the split with three techniques. Hole-punching: cache the page, fetch the genuinely dynamic fragments (cart, inventory) separately and late. Smart invalidation: tie cache lifetime to catalog events - a price change purges exactly the affected pages. Personalization-safe caching: vary cached versions by segment rather than by individual, so caching survives merchandising without leaking across shoppers.
What to ask a vendor
Four questions separate real storefront edge caching from marketing: What is the cache-hit ratio on HTML for a store like mine? How are cart and inventory fragments handled? How fast does a price change propagate? And what is the failure mode - does a stale page ever show wrong prices, and who catches it? Vendors with real implementations answer in specifics.
The takeaway
Full-page edge caching is the single biggest speed lever left for most storefronts, and the only one that improves with distance from the origin. The technology is ready; the diligence is in the dynamic-state details.