# Cache-Control Headers

**`SWS`** provides support for *arbitrary* [`Cache-Control`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control) HTTP header specifying `public` and `max-age` response directives.

This feature is enabled by default and can be controlled by the boolean `-e, --cache-control-headers` option or the equivalent [SERVER_CACHE_CONTROL_HEADERS](./../configuration/environment-variables.md#server_cache_control_headers) env.

!!! tip "Customize HTTP headers"

    If you want to customize HTTP headers on demand then have a look at the [Custom HTTP Headers](custom-http-headers.md) section.

## Cache-Control Max-Age

Control headers are applied only to the following file types with the corresponding `max-age` values.

### One day

A `max-age` of *one day* duration is used by default.

!!! info "Note"

    One-day `max-age` for example includes `html` and other file types.

### One hour

A `max-age` of *one hour* is applied only to the following file types.

```txt
atom, json, rss, xml
```

### One year

A `max-age` of *one year* is applied only to the following file types.

```txt
avif, bmp, bz2, css, doc, gif, gz, htc, ico, jpeg, jpg, js, jxl, map, mjs, mp3, mp4, ogg, ogv, pdf, png, rar, rtf, tar, tgz, wav, weba, webm, webp, woff, woff2, zip
```

Below is an example of how to enable the feature.

```sh
static-web-server \
    --port 8787 \
    --root ./my-public-dir \
    --cache-control-headers true
```
