Optimize Apache with mod_pagespeed

mod_pagespeed is a Google-developed Apache module that automatically optimizes web pages and assets to improve site speed. It rewrites HTML, CSS, JavaScript, and images on-the-fly without requiring changes to your application code. This guide covers installing and configuring mod_pagespeed for production use.

Install mod_pagespeed

# Debian/Ubuntu
wget https://dl-ssl.google.com/dl/linux/direct/mod-pagespeed-stable_current_amd64.deb
sudo dpkg -i mod-pagespeed-stable_current_amd64.deb
sudo apt -f install  # Fix dependencies

# RHEL/Rocky
wget https://dl-ssl.google.com/dl/linux/direct/mod-pagespeed-stable_current_x86_64.rpm
sudo rpm -U mod-pagespeed-stable_current_x86_64.rpm

# Restart Apache
sudo systemctl restart apache2

# Verify
curl -sI http://localhost | grep X-Mod-Pagespeed

Configure Optimization Filters

# /etc/apache2/mods-available/pagespeed.conf

    ModPagespeed on
    ModPagespeedFileFetchPath /var/mod_pagespeed/

    # Core filters (enabled by default)
    ModPagespeedRewriteLevel CoreFilters

    # Enable additional useful filters
    ModPagespeedEnableFilters collapse_whitespace
    ModPagespeedEnableFilters combine_css
    ModPagespeedEnableFilters combine_javascript
    ModPagespeedEnableFilters convert_jpeg_to_progressive
    ModPagespeedEnableFilters convert_jpeg_to_webp
    ModPagespeedEnableFilters convert_png_to_jpeg
    ModPagespeedEnableFilters defer_javascript
    ModPagespeedEnableFilters inline_css
    ModPagespeedEnableFilters inline_javascript
    ModPagespeedEnableFilters lazyload_images
    ModPagespeedEnableFilters move_css_to_head
    ModPagespeedEnableFilters optimize_images
    ModPagespeedEnableFilters prioritize_critical_css
    ModPagespeedEnableFilters responsive_images
    ModPagespeedEnableFilters rewrite_css
    ModPagespeedEnableFilters rewrite_images
    ModPagespeedEnableFilters rewrite_javascript

    # Image optimization settings
    ModPagespeedJpegRecompressionQuality 75
    ModPagespeedImageMaxRewritesAtOnce 8
    ModPagespeedImageResolutionLimitBytes 32000000

    # CSS/JS optimization
    ModPagespeedCssInlineMaxBytes 4096
    ModPagespeedJsInlineMaxBytes 2048
    ModPagespeedMaxCombinedJsBytes 200000

    # Cache settings
    ModPagespeedFileCachePath /var/cache/mod_pagespeed
    ModPagespeedFileCacheSizeKb 102400
    ModPagespeedFileCacheCleanIntervalMs 3600000
    ModPagespeedLRUCacheKbPerProcess 1024
    ModPagespeedLRUCacheByteLimit 16384

    # Admin and statistics
    
        Order deny,allow
        Deny from all
        Allow from 127.0.0.1
    

    ModPagespeedStatistics on
    ModPagespeedStatisticsLogging on

Per-VirtualHost Configuration

    ServerName example.com

    # Override global settings per site
    ModPagespeed on

    # Disable for specific paths
    
        ModPagespeed off
    

    # Disable for specific user agents (crawlers)
    ModPagespeedDisallow "*/api/*"

    # Whitelist domains for resource rewriting
    ModPagespeedDomain https://example.com
    ModPagespeedDomain https://cdn.example.com
    ModPagespeedMapRewriteDomain https://cdn.example.com https://example.com

Verify Optimizations

# Check pagespeed headers
curl -sI https://example.com | grep -i pagespeed

# View statistics
curl http://localhost/pagespeed_admin/statistics

# View active filters
curl http://localhost/pagespeed_admin/config

# Test with Google PageSpeed Insights
# Before and after enabling mod_pagespeed

Best Practices

• Start with CoreFilters and add filters incrementally
• Test thoroughly: Some filters can break JavaScript-heavy applications
• Disable for admin areas and API endpoints to avoid interference
• Monitor cache size: mod_pagespeed's cache can grow large
• Use with a CDN: mod_pagespeed + CDN = maximum performance
• Check image quality: Adjust JpegRecompressionQuality for your quality/speed balance