# Site Health Check for Compression and Browser Caching

> Adds a Site Health test that requests your homepage and one of your theme's stylesheets and reports whether text files are compressed (gzip or Brotli) and whether static files get long browser cache lifetimes.

- Type: PHP
- Runs: Admin only
- Category: [Performance](https://wpide.com/library/category/performance/)
- Tags: site-health, compression, caching
- Author: WPIDE Team
- Installs: 0
- Updated: 2026-10-28
- Page: https://wpide.com/library/perf-compression-caching-site-health/

## Code

```php
add_filter( 'site_status_tests', function ( $tests ) {
    $tests['direct']['wpide_compression_cache'] = array(
        'label' => 'Compression and browser caching',
        'test'  => function () {
            $result = get_transient( 'wpide_compression_check' );

            if ( false === $result ) {
                $args = array( 'timeout' => 8, 'sslverify' => apply_filters( 'https_local_ssl_verify', false ), 'headers' => array( 'Accept-Encoding' => 'gzip, br' ), 'decompress' => false );
                $home = wp_remote_get( home_url( '/' ), $args );
                $css  = wp_remote_get( get_stylesheet_uri(), $args );
                $cc   = (string) wp_remote_retrieve_header( $css, 'cache-control' );
                $age  = preg_match( '/max-age=(\d+)/', $cc, $m ) ? (int) $m[1] : 0;
                $result = array(
                    'compressed' => ! is_wp_error( $home ) && '' !== (string) wp_remote_retrieve_header( $home, 'content-encoding' ),
                    'cached'     => ! is_wp_error( $css ) && ( $age >= 30 * DAY_IN_SECONDS || '' !== (string) wp_remote_retrieve_header( $css, 'expires' ) ),
                    'error'      => is_wp_error( $home ),
                );
                set_transient( 'wpide_compression_check', $result, 12 * HOUR_IN_SECONDS );
            }

            $problems = array();
            if ( ! $result['compressed'] ) {
                $problems[] = 'pages are not compressed with gzip or Brotli';
            }
            if ( ! $result['cached'] ) {
                $problems[] = 'static files such as CSS do not have a long browser cache lifetime';
            }

            return array(
                'label'       => $result['error'] ? 'Compression and caching could not be checked' : ( $problems ? 'Compression or browser caching is missing' : 'Compression and browser caching are enabled' ),
                'status'      => $problems ? 'recommended' : 'good',
                'badge'       => array( 'label' => 'Performance', 'color' => 'blue' ),
                'description' => '<p>' . esc_html( $problems ? 'Your server reports that ' . implode( ' and ', $problems ) . '. Ask your host to enable compression and long cache headers for static files.' : 'Text responses are compressed and static files are cached by browsers.' ) . '</p>',
                'test'        => 'wpide_compression_cache',
            );
        },
    );

    return $tests;
} );
```

## Notes

Both are configured in your web server or CDN, not in WordPress; the result is cached for 12 hours.

## How to use it

Install the free WPIDE plugin (https://wordpress.org/plugins/wpide/), find "Site Health Check for Compression and Browser Caching" in its snippet library and add it in one click; or create a new PHP snippet in WPIDE (or any code snippets plugin) and paste the code above. More snippets: https://wpide.com/library/