CDN and Edge Caching Strategy in 2026

CDN strategy is half-art half-math. The four axes break it down; the discipline is sustaining cache-hit-rate.

Why CDN matters

Origin paid every request without CDN.

With CDN: 80%+ of requests hit edge; origin sees a fraction.

Four strategy axes

• TTL: how long edge caches keep.
• Key: what makes a cache entry unique.
• Invalidation: how to purge stale.
• Vary: what request properties change the cached response.

CDN comparison

Cloudflare: cheapest at scale; broad features.

AWS CloudFront: tight AWS integration.

Fastly: fastest invalidation; programmable edge.

Akamai: enterprise; expensive.

Cache-hit target

Target hit-rate: 80% for static assets; 60% for dynamic; 30% for personalized.

Below target: review TTL + key; usually one of those is wrong.

Antipatterns

• No CDN for static. Origin paid for every request.
• CDN with key including session. Hit-rate dies.
• No invalidation strategy. Stale content for hours.

What to do this week

Three moves. (1) Apply this pattern to your slowest production endpoint. (2) Measure p99 before/after. (3) Document the win and ship the runbook so the team can reproduce.