reduce origin load with edge caching

To reduce origin load with edge caching, the goal is to serve as many requests as possible from CDN/edge nodes instead of your origin server.

Practical ways to do it

1) Cache more content at the edge

• Set longer Cache-Control for static assets:
  • Cache-Control: public, max-age=31536000, immutable
• Cache HTML where possible:
  • Use short TTLs if content changes often
  • Use stale-while-revalidate to keep serving cached content while refreshing in the background

2) Make cache keys efficient

• Avoid unnecessary variation in cache keys
• Only vary on what truly changes the response:
  • Accept-Encoding
  • Accept-Language only if needed
  • Device-specific headers only if required
• Strip query parameters that don’t affect content

3) Use edge caching rules

• Cache by path patterns:
  • /assets/*
  • /images/*
  • /api/public/*
• Bypass cache for dynamic/admin/authenticated pages

4) Increase cache hit ratio

• Normalize URLs
• Redirect or rewrite to canonical paths
• Remove tracking params from cacheable content
• Use consistent hostnames and protocols

5) Use stale content intelligently

• stale-while-revalidate
• stale-if-error These reduce origin spikes during traffic bursts or temporary failures.

6) Cache API responses when safe

• Cache GET requests that are:
  • public
  • identical for many users
  • not personalized
• Use short TTLs and explicit invalidation if needed

7) Purge selectively

• Invalidate only changed objects, not the whole cache
• Use versioned asset filenames so you rarely need purges

8) Collapse duplicate requests

• Enable request coalescing / origin shield / tiered caching if available
• This prevents many edge misses from hitting origin simultaneously

Example headers

Static assets:

Cache-Control: public, max-age=31536000, immutable

HTML with revalidation:

Cache-Control: public, max-age=60, stale-while-revalidate=300, stale-if-error=600

API response:

Cache-Control: public, max-age=30, stale-while-revalidate=120

Best practices

• Prefer caching at the edge over origin-side caching alone
• Use observability:
  • cache hit ratio
  • origin fetch rate
  • bytes served from edge
  • 5xx/latency during cache misses
• Test carefully for personalized or sensitive content

If you want, I can give you:

1. a Cloudflare/Fastly/Akamai-specific setup, or
2. a concrete caching policy for static files, HTML, and APIs.