PageSpeed Insights may report that your site doesn’t cache files in the browser or doesn’t compress its pages:

• Use efficient cache lifetimes means that your server doesn’t tell browsers how long to keep files such as images, CSS and JavaScript. Older reports called this “Leverage browser caching” or “Serve static assets with an efficient cache policy”.
• Document request latency includes a compression check. If it says the response was uncompressed, your server sends pages without compression. Older reports called this “Enable text compression”.

Our guide to optimizing WordPress for speed explains both in more detail.

If you use a caching plugin or your host offers caching, check its settings first. It may already do this for you.

Add the code to .htaccess

These steps work on Apache servers. If your host uses Nginx, .htaccess files have no effect, so ask your host to turn on caching and compression.

1. Open your site’s files with FTP or your hosting file manager, and find the .htaccess file in your WordPress folder (the folder with wp-config.php).
2. Download a backup copy of .htaccess.
3. Add one or both of the code snippets below to the end of the file, and save it.
4. Run PageSpeed Insights again.

Browser caching

# ----------------------------------------------------------------------
# | Expires headers                                                    |
# ----------------------------------------------------------------------

# Serve resources with far-future expires headers.
#
# (!) If you don't control versioning with filename-based
# cache busting, you should consider lowering the cache times
# to something like one week.
#
# https://httpd.apache.org/docs/current/mod/mod_expires.html

<IfModule mod_expires.c>

    ExpiresActive on
    ExpiresDefault                                      "access plus 1 month"

  # CSS

    ExpiresByType text/css                              "access plus 1 year"


  # Data interchange

    ExpiresByType application/atom+xml                  "access plus 1 hour"
    ExpiresByType application/rdf+xml                   "access plus 1 hour"
    ExpiresByType application/rss+xml                   "access plus 1 hour"

    ExpiresByType application/json                      "access plus 0 seconds"
    ExpiresByType application/ld+json                   "access plus 0 seconds"
    ExpiresByType application/schema+json               "access plus 0 seconds"
    ExpiresByType application/vnd.geo+json              "access plus 0 seconds"
    ExpiresByType application/xml                       "access plus 0 seconds"
    ExpiresByType text/calendar                         "access plus 0 seconds"
    ExpiresByType text/xml                              "access plus 0 seconds"


  # Favicon (cannot be renamed!) and cursor images

    ExpiresByType image/vnd.microsoft.icon              "access plus 1 week"
    ExpiresByType image/x-icon                          "access plus 1 week"

  # HTML

    ExpiresByType text/html                             "access plus 0 seconds"


  # JavaScript

    ExpiresByType application/javascript                "access plus 1 year"
    ExpiresByType application/x-javascript              "access plus 1 year"
    ExpiresByType text/javascript                       "access plus 1 year"


  # Manifest files

    ExpiresByType application/manifest+json             "access plus 1 week"
    ExpiresByType application/x-web-app-manifest+json   "access plus 0 seconds"
    ExpiresByType text/cache-manifest                   "access plus 0 seconds"


  # Markdown

    ExpiresByType text/markdown                         "access plus 0 seconds"


  # Media files

    ExpiresByType audio/ogg                             "access plus 1 month"
    ExpiresByType image/bmp                             "access plus 1 month"
    ExpiresByType image/gif                             "access plus 1 month"
    ExpiresByType image/jpeg                            "access plus 1 month"
    ExpiresByType image/png                             "access plus 1 month"
    ExpiresByType image/svg+xml                         "access plus 1 month"
    ExpiresByType image/webp                            "access plus 1 month"
    ExpiresByType video/mp4                             "access plus 1 month"
    ExpiresByType video/ogg                             "access plus 1 month"
    ExpiresByType video/webm                            "access plus 1 month"


  # Web fonts

    # Collection
    ExpiresByType font/collection                       "access plus 1 month"

    # Embedded OpenType (EOT)
    ExpiresByType application/vnd.ms-fontobject         "access plus 1 month"
    ExpiresByType font/eot                              "access plus 1 month"

    # OpenType
    ExpiresByType font/opentype                         "access plus 1 month"
    ExpiresByType font/otf                              "access plus 1 month"

    # TrueType
    ExpiresByType application/x-font-ttf                "access plus 1 month"
    ExpiresByType font/ttf                              "access plus 1 month"

    # Web Open Font Format (WOFF) 1.0
    ExpiresByType application/font-woff                 "access plus 1 month"
    ExpiresByType application/x-font-woff               "access plus 1 month"
    ExpiresByType font/woff                             "access plus 1 month"

    # Web Open Font Format (WOFF) 2.0
    ExpiresByType application/font-woff2                "access plus 1 month"
    ExpiresByType font/woff2                            "access plus 1 month"


  # Other

    ExpiresByType text/x-cross-domain-policy            "access plus 1 week"

</IfModule>

Compression

<IfModule mod_deflate.c>
    <IfModule mod_filter.c>
        AddOutputFilterByType DEFLATE "application/javascript" \
                                      "application/json" \
                                      "application/ld+json" \
                                      "application/manifest+json" \
                                      "application/rss+xml" \
                                      "application/xhtml+xml" \
                                      "application/xml" \
                                      "font/otf" \
                                      "font/ttf" \
                                      "image/svg+xml" \
                                      "image/x-icon" \
                                      "text/css" \
                                      "text/html" \
                                      "text/javascript" \
                                      "text/plain" \
                                      "text/xml"
    </IfModule>
</IfModule>

Both snippets are based on the HTML5 Boilerplate server configuration for Apache.