Web Performance1 min read
Edge Caching, SSR, and Cache Components — Picking Boundaries in Next.js
By Priyatham Rama Sai
Static marketing shell with edge cache plus dynamic islands for account data cut TTFB without turning the whole app client-only. We draw lines by data freshness requirements, not by what is easiest to fetch in RSC.
Fragmentation strategy
Ship fast global HTML for anonymous traffic. Authenticated views may need regional data — align cache keys with auth and personalization rules or you leak pages between users.
Partial dynamic
Composition patterns isolate slow queries so one bad join does not block entire route shells. Observability per segment shows which island drags LCP.
Invalidation discipline
Tag-based revalidation beats time-only TTL when product updates must land predictably — document who triggers purges after deploys.