Cloudflare Etag header shows whether cached resource versions in the browser correspond to those on the web server. Let’s look into the details. At Bobcares, with our Server Management Services, we can handle your server-related issues.

Cloudflare Etag Header

The HTTP protocol used by the World Wide Web includes the ETag, or entity tag. If a resource is cached in the browser and on the web server, ETag headers let us know if they are the same version. ETags are saved in a visitor’s browser. The browser compares each ETag to the one it stored when a visitor returns to a site.

Strong and weak ETags set up on the origin web server are supported by Cloudflare. Let’s look into the details of Strong ETag and Weak ETag.

Cloudflare Strong Etag Header

Strong ETag headers verify that the resource is the same byte for byte both on the web server and in the browser cache. Customers on lower-tier plans can enable strong ETag headers using Cache Rules, whereas domains on Enterprise plans do so via a Respect Strong ETags Page Rule. If not, strong ETag headers are changed to weak ones. Additionally, enclose a strong ETag header in quotation marks, otherwise, Cloudflare will erase the ETag rather than change it to a weak ETag.

Without a Page Rule, Cloudflare keeps the origin web server’s strong ETags in the following cases: the functionalities of Rocket Loader, Minification, Email Obfuscation, and Railgun are disabled, and the content is gzipped on the origin server before being sent. The origin also delivers the gzipped content with a powerful ETag header.

Rocket Loader, Minification, Email Obfuscation, and Railgun are all automatically turned off when Strong ETags are enabled via Cloudflare. Cloudflare does not send ETag headers to the origin of a cache miss that occurs on a cacheable resource. This is so that Cloudflare can fill its cache, which needs the entire response body.

Cloudflare Weak Etag Header

A cached resource is logically comparable to the version on the web server but may not be byte-for-byte identical, according to weak ETag headers. On all plans, Cloudflare supports weak ETag headers. Disable Email Obfuscation and Automatic HTTPS Rewrites when using weak ETag headers to prevent Cloudflare from removing the ETag headers that were set by the origin web server.

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Conclusion

To conclude, the article differentiates between the Strong ETag and Weak ETag headers in Cloudflare.