Caching

Page caching, browser caching, cache preload, and automatic invalidation

How page caching works

ProRank page caching generates static HTML files and serves them on subsequent requests, bypassing PHP and database queries. Cache preloading keeps frequently visited pages warm. For CDN provider setup and URL rewriting, see the Caching & CDN page.

Core Features

Local Server Caching

Page cache on your origin server
Object cache stats (when a compatible object cache backend is active)
Automatic cache invalidation on updates
Cache preloading via WP-Cron

CSS Optimisation

CSS minification
Combine CSS files
Inline @import statements
Cache external CSS locally
Font-display optimisation

JavaScript Optimisation

Defer JavaScript loading
Delay until user interaction (Beta)
Exclude critical scripts

Configuration Guide

1. Local Cache Settings

WordPress Adminphp

// Navigate to: ProRank SEO > Performance

// General Tab Settings:
- Enable Page Cache: ON
- Cache Lifetime: 3600 seconds
- Exclude URLs: /checkout/, /cart/, /my-account/
- Cache Mobile Separately: OFF (unless needed)

CDN

For CDN provider setup, URL rewriting, and purge configuration, see the Caching & CDN page.

3. Preloading Configuration

Cache Preloadingphp

// Preload Tab Settings:
- Enable Cache Preloading: ON
- Preload Mode: Sitemap (recommended)
- Schedule: Daily

// What it does:
// - Visits pages to warm LOCAL server cache

4. Advanced Optimisations

CSS/JS Settingsphp

// CSS Optimisation:
- Enable CSS Minification: ON
- Combine CSS Files: ON (test first)
- Inline @import Statements: ON
- Cache External CSS: ON
- Optimize Font Display: ON
- Cache Lifetime (days): 30

// JavaScript Optimisation:
- Defer JavaScript: ON
- Delay JavaScript: OFF (delays scripts until user interaction)
- Exclude Scripts: jquery.min.js, critical.js

REST API Endpoints

Cache Statistics

GET /wp-json/prorank-seo/v1/cache/stats

{
  "hit_rate": 85.5,
  "total_cached": 150,
  "cache_size": "45.2 MB",
  "bandwidth_saved": "1.2 GB",
  "cache_efficiency": 92.3
}

Clear Cache

POST /wp-json/prorank-seo/v1/cache/clear

Clears all page cache files

CSS Cache Management

POST /wp-json/prorank/v1/performance/css-cache/clear

Clears the CSS minification cache.

CSS Preview

POST /wp-json/prorank/v1/performance/css/preview

Preview CSS optimisation results for a given URL.

Cache Preload

POST /wp-json/prorank-seo/v1/cache/preload

Trigger a cache preload run.

WP-CLI Commands

# Preload cache (warms local server cache)
wp prorank cache preload

# Database optimisation
wp prorank db-optimize

Real Performance Impact

With Page Cache Enabled

✅ Static HTML served directly, bypassing PHP
✅ Reduced database queries per page load
✅ Lower server CPU and memory usage
✅ Consistent response times on repeat visits

Without Page Cache

⚠️ Every request runs full WordPress PHP stack
⚠️ Higher server load under traffic spikes
⚠️ Variable response times
⚠️ More database queries per page load

Common Issues & Solutions

Cache Not Clearing

Stale cached HTML may persist after content changes.

Solution: Use the admin bar Clear Cache button. For CDN purge setup, see the Caching & CDN page.

CSS Changes Not Showing

Minified CSS cached for 30 days by default.

Solution: Clear CSS cache from Advanced tab or reduce cache lifetime.

JavaScript Errors

Delay execution can break interactive elements.

Solution: Exclude critical scripts or disable delay execution.

Logged-in Users See Cached Content

Cache serving to authenticated users.

Solution: Add login cookies to exclude list.

Beta Features

Enable with Caution

Beta features are experimental and may cause issues. Test thoroughly on staging first.

WebSocket Monitoring (Beta)

Experimental internal work for live cache status indicators.

Status: Not exposed as a public/stable feature in current releases.

Understanding the Architecture

What you have: One WordPress server (your hosting) that can integrate with CDN services.

What caching does: Reduces server processing time and bandwidth usage.

What preloading does: Warms your local server cache, not CDN edges.

This plugin optimizes your single server and integrates with CDN providers for global reach. We don't create multiple servers or fake infrastructure.