Next.js: Слои кеширования (request/data/full route) — компромиссы и trade-offs

Caching — power on-by-default с footguns; Next 15 uncached-by-default снижает stale surprises.

Разбор

• On-by-default power, off-by-default footguns. Data + Full Route caches могут сделать dynamic app static и fast — или stale hours если forgot opt-in. Next 15 flip — меньше speed out-of-box, меньше «why stale?».
• Tag-based beats time-based когда correctness matters. revalidate: 3600 — hour stale; revalidateTag('products') от mutation — correct and fast. On-demand first, time fallback.
• Когда НЕ cache: per-user или security-sensitive — no-store или dynamic rendering. Shared cache user A → user B — real incident.

Итог

Prefer tags + explicit opt-in; never cache personalized/security-sensitive data shared.