Which CDN Caching Strategy Cuts Bandwidth Fastest?
If you want the fastest, biggest cut in CDN bandwidth, turn on Cache Everything at the edge with long TTLs, serve immutable versioned assets, and back it with tiered caching or an origin shield.
You will stop most requests before they ever touch origin, and for some businesses, this often means origin egress drop by 60 to 95 percent in hours without code changes beyond asset versioning.
Direct Path To Minimum Bandwidth
You want the CDN caching strategy that shrinks bills and protects origin right now, and the clear winner is a combination you can think of as Edge‑First Immutable Caching:
- Cache Everything at the edge for all safe GET responses.
- Use long TTLs and immutable headers for assets that change only when you deploy.
- Version file names so you never need a blind CDN cache clear.
- Turn on tiered caching or a single origin shield so your lower-tier POPs fetch from a near parent, not from your origin.
- Serve stale-while-revalidate and collapse concurrent misses so bursts do not amplify traffic.
I like this approach because it removes the two biggest bandwidth leaks in a caching CDN: unnecessary cache variance and unnecessary trips to origin.
You will keep it approachable for non-tech folks by remembering one sentence. If a file’s content only changes when you ship a new version, give it a very long shelf life and a unique versioned name.
Why This Beats Alternatives On Bandwidth
Bandwidth is just bytes that leave origin. Reduce origin requests and you reduce origin bytes. Cache Everything directly targets both sides:
- It maximizes hit ratio by caching full HTML for anonymous pages and all static assets.
- It reduces miss amplification by routing misses through a tier that can satisfy many POPs.
Think of CDN vs cache not as two different ideas but as layers of one system. The CDN cache is the first and best place to stop a request.
Every additional stop, header, or cookie that changes the cache key is a potential miss and a potential byte leaving origin.
Bandwidth Cut Leaderboard
Here is how the top tactics stack up when the goal is purely to shrink origin egress fast. The numbers are directional, not guarantees.
Exact Settings To Flip First
You want settings that most CDNs support regardless of brand. I would start with these and keep the language vendor-neutral.
- Default action: Cache Everything for GET and HEAD where the response is public and not personalized.
- Asset headers: Cache-Control: public, max-age=31536000, immutable for versioned assets.
- HTML where safe: Cache-Control: public, s-maxage=600, stale-while-revalidate=30, stale-if-error=86400.
- Tiered caching or origin shield: enabled, with a single shield region near origin.
- Request collapsing or origin coalescing: enabled, so one miss refreshes many.
- Cache-key rules: ignore query param order, strip known tracking params like utm_*, fbclid, gclid.
- Cookies: ignore or strip cookies from cache key for assets and anonymous HTML.
- Compression: Enable Brotli and Gzip at edge, and store precompressed variants if your CDN supports it.
- Negative caching: small TTLs for 404, 301, 302, and some 5xx to avoid miss loops.
You will notice none of this forces a blanket CDN cache busting workflow. That is the point. Versioned assets sidestep global purges so your CDN cache keeps doing its job even during frequent releases.
What To Cache And For How Long
Map content types to simple, safe TTLs. This is where you cut most bandwidth without breaking freshness.
Avoid Accidental Busting And Unnecessary Purges
CDN cache busting is sometimes needed, but constant purges defeat the point of a CDN cache. Prefer deterministic, content-based busting:
- Fingerprint filenames with a hash, not a query string.
- Mark them immutable so browsers and the CDN both keep them.
- When you do need to invalidate, scope to a tag, prefix, or exact URL instead of a global CDN cache clear.
You will keep your hit ratio steady across releases, and your team will stop thinking of purges as a safety blanket.
