{
"url": "https://example.com/",
"finalUrl": "https://example.com/",
"statusCode": 200,
"verdict": "heuristically_cacheable",
"cacheControl": {
"raw": null,
"directives": {}
},
"expires": {
"raw": null,
"valid": null
},
"validators": {
"etag": null,
"etagType": null,
"lastModified": "Sun, 04 Oct 2026 07:03:47 GMT"
},
"vary": [],
"age": 2302,
"freshness": {
"browserSeconds": 3518,
"browserSource": "heuristic",
"sharedSeconds": 3518,
"sharedSource": "heuristic"
},
"browserCacheable": true,
"sharedCacheable": true,
"canRevalidate": true,
"cdnHeaders": {
"cf-cache-status": "HIT"
},
"issues": [
{
"severity": "warning",
"code": "no_cache_headers",
"message": "Neither Cache-Control nor Expires is set. Caches fall back to a Last-Modified based heuristic or re-request every time."
},
{
"severity": "info",
"code": "heuristic_freshness",
"message": "No explicit freshness is set, so caches may use roughly 10% of the Last-Modified age as a heuristic lifetime. Behavior can differ between caches."
}
],
"cached": true
}
curl --location --request GET 'https://zylalabs.com/api/14097/cache+headers+analyzer+api/34823/analyze+url+http+cache+headers' --header 'Authorization: Bearer YOUR_API_KEY'
After signing up, every developer is assigned a personal API access key, a unique combination of letters and digits provided to access to our API endpoint. To authenticate with the Cache Headers Analyzer API simply include your bearer token in the Authorization header.
| Header | Description |
|---|---|
Authorization
|
Required
Should be Bearer access_key. See "Your API Access Key" above when you are subscribed.
|
No long-term commitment. Upgrade, downgrade, or cancel anytime. Free Trial includes up to 50 requests.
The endpoint returns a structured analysis of caching headers for a given URL, including cacheability verdicts, freshness lifetimes, and a list of potential issues related to caching configurations.
Key fields include `url`, `finalUrl`, `statusCode`, `verdict`, `cacheControl`, `expires`, `validators`, `vary`, `age`, `freshness`, `browserCacheable`, `sharedCacheable`, and `issues`, each providing specific insights into caching behavior.
The response is structured in JSON format, with nested objects for cache control directives, freshness values, validators, and issues, allowing users to easily parse and interpret the caching information.
The endpoint provides information on cacheability, freshness lifetimes, cache control directives, expiration dates, validation methods, and any misconfigurations or issues detected in the caching headers.
The primary parameter is the target URL to analyze. Additionally, users can include `fresh=1` to bypass the cached results and get the most recent analysis.
Typical use cases include optimizing CDN configurations, conducting performance audits, ensuring compliance with caching standards, and troubleshooting caching issues in web applications.
Data accuracy is maintained by following the specifications outlined in RFC 9111 and RFC 9110, ensuring that the analysis reflects standard caching behaviors and practices.
Users can utilize the returned data to identify caching issues, optimize cache settings, and improve website performance by understanding how different headers affect cacheability and freshness.
To obtain your API key, first sign in to your account and navigate to the API you want to use. From the API's Pricing section, choose a plan and complete the subscription process. Once subscribed, return to the API page and you will see your API Access Key displayed at the top of the documentation page. You can use this key to authenticate your requests.
You can’t switch APIs during the free trial. If you subscribe to a different API, your trial will end and the new subscription will start as a paid plan.
The free trial lasts for 7 days and allows you to make up to 50 API requests.
No, the free trial is available only once, so we recommend using it on the API that interests you the most. Most of our APIs offer a free trial, but some may not include this option.
Yes. If the API offers a free trial, you will see a "Free 7-Day Trial" option in its Pricing section. The trial lasts for 7 days and allows up to 50 API requests, enabling you to evaluate the API before subscribing to a paid plan.
Zyla API Hub is like a big store for APIs, where you can find thousands of them all in one place. We also offer dedicated support and real-time monitoring of all APIs. Once you sign up, you can pick and choose which APIs you want to use. Just remember, each API needs its own subscription. But if you subscribe to multiple ones, you'll use the same key for all of them, making things easier for you.
You can monitor your API usage through the response headers included with every request:
x-zyla-api-calls-monthly-used: Shows the total number of API requests you have used during the current billing period.
x-zyla-api-calls-monthly-remaining: Shows the number of API requests you have remaining for the current billing period.
Yes, you can cancel your subscription at any time. Simply go to the Pricing section of the API you're subscribed to and click the "Unsubscribe" button.
Please note that upgrades, downgrades, and cancellations take effect immediately. Once your subscription is canceled, access to the service will end immediately, regardless of any remaining API calls in your quota.
Please have a look at our Refund Policy: https://zylalabs.com/terms#refund