Optimizing WordPress For Speed: Caching, Cdns, And Code Optimization
Maximizing the speed and performance of a WordPress site is crucial for providing users with a smooth, seamless browsing experience. There are various potential causes of WordPress slowing down, ranging from bloated databases to inefficient code. Implementing targeted optimizations for caching, content delivery networks (CDNs), images, scripts, themes, plugins, and web servers can significantly improve WordPress speed.
What Causes WordPress to Be Slow?
Common culprits that lead to decreased WordPress performance include:
Excessive Database Queries
Plugins, themes, and other site functionality require frequent queries to the MySQL database to render pages. Too many scripts hitting the database can bottleneck request time. The database cache helps, but often gets overloaded on larger sites.
Unoptimized Images
High resolution, uncompressed images drastically increase page weight and stall browser loading times. Images should be properly sized, compressed, lazy loaded, and served from a CDN.
Excessive Plugins and Themes
Too many plugins and overloaded themes introduce computational bloat, unnecessary HTTP requests, and redundant code. Lean themes like GeneratePress combined with only essential plugins improves efficiency.
Server-Side Issues
Inadequate server specifications, outdated software versions, and suboptimal configuration parameters hamper ability to serve WordPress sites at scale. Upgrading to better hosting, PHP 7.4+, MySQL 5.7+ and caching helps.
Implementing Caching Solutions
Caching stores rendered web pages, SQL query results, snippets of code, and other data in a temporary location so that repeat requests can be served faster. Common WordPress caches include:
Browser Caching with Cache Plugins
Browser caching configures local storage on user devices to retain copies of site assets to avoid re-downloading unchanged resources. Cache plugins add expiration headers to enable browser caching.
Page Caching with WP Rocket
Page caches store the HTML output of urls to serve pages without needing to rebuild the entire WordPress process and database queries. WP Rocket offers advanced page caching and invalidates as content updates.
Object Caching with Redis
Object caching stores database queries, API requests, metadata, and fragments of rendered code in memory via Redis for rapid reuse. This reduces trips to slower disk-based databases when rebuilding pages and components.
Enabling a CDN (Content Delivery Network)
A CDN is a globally distributed network of proxy servers that provide cached versions of WordPress sites and assets to users based on geographic proximity for faster delivery speeds.
How a CDN Works
CDNs have local Points of Presence (POPs) worldwide that cache copies of websites. Requests get routed to the nearest POP so content doesn’t have to travel across continents to reach the visitor.
Recommended CDNs for WordPress
Top CDNs proven to effectively cache and accelerate WordPress include KeyCDN, Cloudflare, StackPath, and Amazon CloudFront based on benchmarks and customer usage volume.
Configuring a CDN in wp-config.php
Many CDNs have WordPress plugins to simplify setup. Alternatively wp-config.php can be configured manually to point assets and media URLs to a custom CDN subdomain for offloading static files.
Optimizing Images
With images constituting over two-thirds of bytes downloaded on average webpages, image optimization can yield noticeable speedups.
Using Optimized JPGs and PNGs
JPGs and PNGs should be compressed with tools like ShortPixel to squash file sizes. Images should have their pixel dimensions sized appropriately for layouts to limit excess pixels.
Serving Images Responsively
Responsive images use srcset and sizes attributes to serve multiple cropped image variants tailored to visitor viewports. This avoids wasting bandwidth on extra pixels.
Lazy Loading Images
Lazy load plugins defer offscreen images from downloading until visitors scroll to them. This eliminates unnecessary image requests on initial page load for faster rendering.
Minifying CSS and JavaScript
Reducing code cruft in CSS and JS files through minification and combining streamlines downloads through decreased filesize and requests.
Plugins for Minification
Automattic’s Autoptimize handles script/style minify+concatenate+cache automatically. Alternative plugins like WP Fastest Cache also combine+minimize assets.
Manually Optimizing Assets
For ultimate control, developers can manually parse for code efficiencies in CSS/JS files, minify with Grunt/Gulp, compile with Webpack, and serve minified/cached versions from CDN origins.
Using Efficient Code in Themes and Plugins
Carefully coded themes and plugins improve performance by avoiding sluggish functions and database queries where possible.
Avoiding Inefficient Loops and Queries
Lean PHP avoids slow for/foreach loops. Database writes/reads are minimized with batched queries where possible via approachs like transient caching.
Coding with Performance in Mind
Efficient plugins limit dependencies, payload size, computational complexity, and follow WordPress coding best practices focused on performance.
Monitoring WordPress Performance
Actionable performance insights are uncovered by tracking speed metrics over time. This identifies optimization impact and areas needing additional work.
Using PageSpeed Insights
PageSpeed Insights analyzes site loading data surfaced in Chrome User Experience Report and Field Data to quantify real-world visitor performance.
Enabling Debug Mode
WordPress debug mode adds query and filesize output to pages for diagnosing limiting factors. Stack traces help pinpoint codeinefficiencies.
Monitoring with New Relic
New Relic APM traces waterfall timing metrics, PDO statements, caching efficiency, REST API performance, and errors during requests for in-depth performance inspection and debugging.
