# S-Cache Header Explained

Whenever you use our smoxy with Acceleration or Image Optimization enabled, you will encounter the `S-Cache` header related to caching. This header indicate the cache status across different layers of our content delivery infrastructure.

## HIT

The resource was found in smoxy's cache.

## MISS

The resource was not found in smoxy's cache and was served from the origin web server. To prevent browsers from caching the response during a cache miss, smoxy sets the response header `cache-control: no-cache, no-store, must-revalidate`. This ensures users always receive the correct content once it becomes available in smoxy's cache.

## BYPASS

When the [Cache Control Header](https://docs.smoxy.eu/en/basic-configuration#cache-control-header-respect) configuration was enabled in the basic configuration and the origin web server instructed smoxy to bypass cache via a `Cache-Control` header set to `no-cache`, `private`, or `max-age=0` .

BYPASS is also returned if your request to your origin web server includes an `http-bypass` header with a valid token or a base64 encoded string of your hostname.

When the returned content type of your request is not eligible for caching, smoxy will also return BYPASS.