WordPress Performance Optimization

Complete guide for optimizing WordPress site performance, Core Web Vitals, and passing speed tests.

Core Web Vitals Targets

Image Optimization

Plugin Stack

1. EWWW Image Optimizer - Best all-around

   • Lossless & lossy compression
   • WebP conversion
   • Lazy loading
   • CDN option (ExactDN)

2. ShortPixel - Alternative with more formats

   • AVIF support
   • Glossy/lossy/lossless modes
   • Bulk optimization

3. Imagify - Simple and effective

   • Three compression levels
   • WebP conversion
   • Resize on upload

EWWW Configuration

// Recommended EWWW settings via wp-config.php or plugin settings

// Enable WebP conversion
define('EWWW_IMAGE_OPTIMIZER_WEBP', true);

// Set maximum dimensions
define('EWWW_IMAGE_OPTIMIZER_MAX_WIDTH', 2560);
define('EWWW_IMAGE_OPTIMIZER_MAX_HEIGHT', 2560);

// Enable lazy loading
define('EWWW_IMAGE_OPTIMIZER_LAZY_LOAD', true);

Manual Image Guidelines

Responsive Images

WordPress generates srcset automatically. Ensure proper sizes:

// Add custom image sizes
function theme_custom_image_sizes() {
    add_image_size('hero', 1920, 1080, true);
    add_image_size('hero-tablet', 1024, 768, true);
    add_image_size('hero-mobile', 768, 1024, true);
    add_image_size('card', 600, 400, true);
    add_image_size('thumb-square', 300, 300, true);
}
add_action('after_setup_theme', 'theme_custom_image_sizes');

Preload Critical Images

// Preload LCP image
function theme_preload_hero() {
    if (is_front_page()) {
        $hero_url = get_theme_file_uri('/assets/images/hero.webp');
        echo '<link rel="preload" as="image" href="' . esc_url($hero_url) . '">';
    }
}
add_action('wp_head', 'theme_preload_hero', 1);

Video Optimization

Self-Hosted Video

1. Compress before upload

   • Use HandBrake or FFmpeg
   • Target: 1-2 MB per minute for web
   • Resolution: 1080p max (720p for backgrounds)
   • Codec: H.264 (MP4) for compatibility, H.265 for smaller size

2. FFmpeg commands

# Compress video for web (H.264, CRF 23 = good quality)
ffmpeg -i input.mp4 -c:v libx264 -crf 23 -preset slow -c:a aac -b:a 128k output.mp4

# Create WebM version (smaller, modern browsers)
ffmpeg -i input.mp4 -c:v libvpx-vp9 -crf 30 -b:v 0 -c:a libopus output.webm

# Extract poster image
ffmpeg -i input.mp4 -ss 00:00:01 -vframes 1 poster.jpg

# Resize to 720p
ffmpeg -i input.mp4 -vf scale=1280:720 -c:v libx264 -crf 23 output-720p.mp4

3. HTML with fallbacks

<video autoplay muted loop playsinline poster="poster.jpg">
    <source src="video.webm" type="video/webm">
    <source src="video.mp4" type="video/mp4">
</video>

External Video Hosting

For longer videos, use:

• YouTube - Free, good performance, ads
• Vimeo - Ad-free, professional
• Bunny Stream - Cheap, fast CDN
• Cloudflare Stream - Good for high traffic

Lazy Load Videos

// Lazy load video on scroll
const videoObserver = new IntersectionObserver((entries) => {
    entries.forEach(entry => {
        if (entry.isIntersecting) {
            const video = entry.target;
            video.src = video.dataset.src;
            video.load();
            videoObserver.unobserve(video);
        }
    });
});

document.querySelectorAll('video[data-src]').forEach(video => {
    videoObserver.observe(video);
});

Caching

LiteSpeed Cache Configuration

// wp-config.php settings
define('LITESPEED_ON', true);
define('LITESPEED_CACHE_DIR', WP_CONTENT_DIR . '/cache/litespeed/');

Recommended LiteSpeed Settings:

Object Cache (Redis)

// wp-config.php
define('WP_REDIS_HOST', '127.0.0.1');
define('WP_REDIS_PORT', 6379);
define('WP_REDIS_DATABASE', 0);
define('WP_CACHE', true);

// Install Redis Object Cache plugin

Transient Caching

// Cache expensive queries
function get_featured_properties() {
    $cache_key = 'featured_properties';
    $properties = get_transient($cache_key);

    if (false === $properties) {
        $properties = new WP_Query([
            'post_type' => 'property',
            'posts_per_page' => 6,
            'meta_key' => '_featured',
            'meta_value' => '1'
        ]);

        set_transient($cache_key, $properties, HOUR_IN_SECONDS);
    }

    return $properties;
}

// Clear cache on update
function clear_property_cache($post_id) {
    if ('property' === get_post_type($post_id)) {
        delete_transient('featured_properties');
    }
}
add_action('save_post', 'clear_property_cache');

Asset Optimization

CSS Optimization

// Remove unused block styles
function theme_remove_block_styles() {
    wp_dequeue_style('wp-block-library');
    wp_dequeue_style('wp-block-library-theme');
    wp_dequeue_style('global-styles');
}
add_action('wp_enqueue_scripts', 'theme_remove_block_styles', 100);

// Defer non-critical CSS
function theme_defer_styles($html, $handle, $href, $media) {
    $defer_handles = ['theme-animations', 'font-awesome'];

    if (in_array($handle, $defer_handles)) {
        return '<link rel="preload" as="style" href="' . $href . '" onload="this.onload=null;this.rel=\'stylesheet\'">' .
               '<noscript><link rel="stylesheet" href="' . $href . '"></noscript>';
    }

    return $html;
}
add_filter('style_loader_tag', 'theme_defer_styles', 10, 4);

JavaScript Optimization

// Defer scripts
function theme_defer_scripts($tag, $handle, $src) {
    $defer_scripts = ['theme-main', 'gsap', 'gsap-scrolltrigger'];

    if (in_array($handle, $defer_scripts)) {
        return str_replace(' src', ' defer src', $tag);
    }

    return $tag;
}
add_filter('script_loader_tag', 'theme_defer_scripts', 10, 3);

// Remove jQuery if not needed
function theme_remove_jquery() {
    if (!is_admin()) {
        wp_deregister_script('jquery');
        wp_deregister_script('jquery-migrate');
    }
}
add_action('wp_enqueue_scripts', 'theme_remove_jquery');

Font Optimization

// Preload fonts
function theme_preload_fonts() {
    $fonts = [
        '/assets/fonts/inter-var.woff2',
        '/assets/fonts/playfair-display.woff2'
    ];

    foreach ($fonts as $font) {
        echo '<link rel="preload" href="' . get_theme_file_uri($font) . '" as="font" type="font/woff2" crossorigin>';
    }
}
add_action('wp_head', 'theme_preload_fonts', 1);

/* Use font-display: swap */
@font-face {
    font-family: 'Inter';
    src: url('fonts/inter-var.woff2') format('woff2');
    font-weight: 100 900;
    font-display: swap;
}

Database Optimization

Regular Maintenance

-- Delete old revisions (keep last 5)
DELETE FROM wp_posts WHERE post_type = 'revision'
AND ID NOT IN (
    SELECT * FROM (
        SELECT ID FROM wp_posts WHERE post_type = 'revision'
        ORDER BY post_date DESC LIMIT 5