Cache Headers Checker
Analyze your website's cache configuration. Check Cache-Control, ETag, Expires and more.
Optimizing Cache Headers
Proper caching is one of the most effective ways to speed up your website. By instructing browsers to store static assets, you minimize server load and speed up repeat visits.
What is Cache-Control?
The Cache-Control header is the primary directive for caching. It tells browsers and CDNs how long they should cache a resource (max-age) and whether it's public or private.
ETag & Revalidation
ETag is a unique identifier for a version of a resource. Browsers use it to check if the file has changed. If it hasn't, the server responds with 304 Not Modified.
Key Cache Headers
Cache-Control
Controls who can cache the response and for how long (max-age).
Expires
An older header specifying an absolute date/time for expiration. Modern browsers prefer Cache-Control.
ETag
Entity Tag. A hash used for cache validation and conditional requests.
Last-Modified
The date and time the object was last modified. Used as a fallback validator.