Cache Headers

free

GET/v1/domain/cache

Analyzes HTTP caching headers to understand how content is cached by browsers and CDNs. Evaluates Cache-Control, ETag, Last-Modified, Vary, and Pragma headers. Detects CDN providers (Cloudflare, Fastly, CloudFront, Vercel, Akamai, Netlify) and reports cache status. Identifies conflicts, security issues, and optimization opportunities.

What It Does

Examines all cache-related HTTP headers and parses Cache-Control directives (max-age, s-maxage, no-cache, no-store, private, public, immutable, stale-while-revalidate, stale-if-error). Detects CDN providers and their cache hit/miss status. Identifies contradictory directives, security risks like Set-Cookie on public responses, and provides a human-readable summary of the caching behavior.

Why It's Useful

Proper caching reduces server load, improves performance, and saves bandwidth. Analyzing cache headers helps identify misconfiguration, contradictory directives, and security issues like sensitive data being cached by shared proxies.

Use Cases

Frontend Developer

Performance Debugging

Debug why content isn't being cached properly by analyzing cache header configuration.

Fix caching issues improving repeat visit performance.

DevOps Engineer

CDN Optimization

Verify cache headers are set correctly for CDN edge caching.

Maximize CDN cache hit rates for better performance and lower origin load.

Security Engineer

Security Review

Ensure sensitive pages have proper no-cache/no-store headers.

Prevent sensitive data from being cached inappropriately.

Parameters

Name	Type	Required	Description
`domain`	string	Required	Domain or full URL — accepts `example.com` or `https://example.com/path`.Example: `https://example.com`
`path`	string	Optional	Optional path to audit a specific asset (e.g. /static/main.css) — static assets typically have very different cache rules than HTMLExample: `/static/main.css`

Response Fields

Field	Type	Description
`domain`	string	The queried domain (bare hostname).
`url`	string	Full URL that was fetched, echoing the protocol used in the request.
`testedUrl`	string	The full URL tested (includes path when supplied)
`statusCode`	number	HTTP status code of the response
`contentType`	string	Content-Type of the response
`isCacheable`	boolean	Whether the response is cacheable
`summary`	string	Human-readable summary of the caching behavior
`cacheControl`	object	Parsed Cache-Control directives (public, private, noCache, noStore, maxAge, sMaxAge, mustRevalidate, proxyRevalidate, noTransform, immutable, staleWhileRevalidate, staleIfError)
`cdnTargeted`	object	CDN-targeted directives — CDN-Cache-Control (RFC 9213), Cloudflare-CDN-Cache-Control, Vercel-CDN-Cache-Control, Surrogate-Control, Cache-Tag, Surrogate-Key
`etag`	string	ETag header value
`etagValidates`	boolean	Whether If-None-Match returns 304. False indicates ETag is set but conditional validation is broken
`lastModified`	string	Last-Modified header value
`vary`	array	Vary header values
`expires`	string	Expires header value
`age`	number	Age header value in seconds
`pragma`	string	Pragma header value (legacy HTTP/1.0)
`effectiveTtl`	number	Effective TTL in seconds (priority: s-maxage > max-age > expires)
`ttlFormatted`	string	Human-readable TTL duration
`remainingTtl`	number	Seconds of freshness remaining at the edge (effectiveTtl − age)
`remainingTtlFormatted`	string	Human-readable remaining freshness
`freshnessPercentLeft`	number	0–100 — percentage of effectiveTtl still fresh
`cdn`	object	CDN detection result (detected, provider, cacheStatus, edgeLocation)
`issues`	array	Caching issues and conflicts detected (including Vary Cookie/Origin antipatterns and stale-at-edge warnings)
`recommendations`	array	Caching optimization and security suggestions

Code Examples

cURL

curl "https://api.edgedns.dev/v1/domain/cache" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d "domain=https://example.com"

JavaScript

const response = await fetch(
  'https://api.edgedns.dev/v1/domain/cache?domain=https%3A%2F%2Fexample.com',
  {
    headers: {
      'Authorization': 'Bearer YOUR_API_KEY'
    }
  }
);

const data = await response.json();
console.log(data);

Python

import requests

response = requests.get(
    'https://api.edgedns.dev/v1/domain/cache',
    headers={'Authorization': 'Bearer YOUR_API_KEY'},
    params={
    'domain': 'https://example.com'
    }
)

data = response.json()
print(data)

Read the full Cache Headers guide

Why it matters, real-world use cases, parameters, response fields, and how to call it from Claude, ChatGPT, or Gemini via MCP.

Read the guide →

External References

Learn more about the standards and protocols behind this endpoint.

Web Vitals MDN HTTP Caching

Try This Endpoint

Test the Cache Headers endpoint live in the playground.

Open in Playground Get API Key