cache-coherence-patterns-reference

Overview

Keeping cached values consistent with their source of truth across tiers (browser, CDN, reverse-proxy, application, data store). Wrong coherence shows as stale data; wrong invalidation shows as cache stampedes per cache-stampede-reference. A pure reference consumed by per-tier test skills.

When to use

• Designing the cache tiers for a new product / endpoint.
• Auditing an existing cache for coherence bugs (stale reads after writes, cross-tenant cache leaks, layered TTLs that fight each other).
• PR review of changes to cache headers, Vary, or invalidation triggers.
• Investigating "users see stale data" reports.