---
url: 'https://docs.smoxy.eu/zones/supported-mime-types.md'
---
# Which MIME types does smoxy support for optimization & caching?

smoxy supports caching and optimization for a selected set of MIME types. The exact behavior depends on which features are enabled in your smoxy configuration.

## Caching Support

### Always cacheable

* text/html
* image/jpeg, image/jpg, image/png, image/webp, image/gif, image/svg+xml

HTML is cached when the zone's **Dynamic cache** is enabled, which allows faster delivery of dynamic or frequently requested pages. Images are cached as part of [Optimization](/zones/optimization).

### Cacheable on request

Every other content type is **off by default** and enabled per zone under [Cacheable content types](/zones/cache#cacheable-content-types) on the Cache page, grouped into five classes:

| Class                  | Content types                                                          |
| ---------------------- | ---------------------------------------------------------------------- |
| **Stylesheets**        | `text/css`                                                             |
| **JavaScript**         | `application/javascript`, `text/javascript`                            |
| **JSON**               | `application/json`, `application/ld+json`, `application/manifest+json` |
| **XML and plain text** | `application/xml`, RSS and Atom feeds, `text/plain`, CSV, Markdown     |
| **Fonts**              | `woff`, `woff2`, `ttf`, `otf`, `eot`                                   |

Two limits apply to every content type: responses larger than **10 MB** are never stored, and video and audio are not cacheable at all, because players request byte ranges rather than whole files.

## Optimization Support

* image/jpeg
* image/jpg
* image/png
* image/webp

When [Optimization](/zones/optimization) is active, these file types are processed and optimized by smoxy. The optimized versions are then cached automatically, ensuring fast delivery and reduced bandwidth usage.

## Automatic Conversion to Modern Formats

When enabling WebP or AVIF in the Optimization settings:

* smoxy automatically converts supported images to WebP or AVIF formats.
* The optimized images are served from the smoxy cache.
* smoxy respects the Accept headers of the client request, ensuring compatibility with all browsers and devices.