ETag Verification

Validate cached content using the ETag response header so the CDN can detect when the origin object has changed.

ETag Verification allows the CDN to determine whether a cached object has changed at the origin after its cache TTL expires.

When enabled, the CDN stores the ETag value returned by the origin. After cache expiration, the CDN can use this value in a conditional request to validate the cached object instead of retrieving the complete object again.

You can manage ETag Verification in the Medianova Control Panel or via the API.

ETag Verification requires the origin to return a valid ETag response header. If no ETag is available, standard cache expiration behavior applies.

Configure ETag Verification

1

Open ETag Verification

Open your CDN Resource and select Caching.

Locate ETag Verification.

2

Enable ETag Verification

Enable the ETag Verification toggle.

When enabled, the CDN stores the ETag value provided by the origin for cached content.

3

Save the Configuration

Select Save in the pending changes bar.

Review the pending changes and confirm the update to apply the configuration to the CDN Resource.

How ETag Validation Works

While a cached object is valid, the CDN serves it from the edge without contacting the origin.

After the cache TTL expires, the CDN uses the stored ETag value to validate the object with the origin. The validation request uses the If-None-Match request header.

If the object has not changed, the existing cached object can be reused without downloading the complete object again. If the object has changed, the CDN retrieves and caches the updated version.

This process can reduce unnecessary data transfer between the origin and CDN while allowing expired cached objects to be validated before they are refreshed.

ETag validation occurs after cache expiration. Enabling this setting does not cause the CDN to contact the origin for every request.