Server-Side caching Vs. Cache Plugin In WordPress

Caching means saving requests to improve performance in the future. Various layers, protocols, and services are involved in WordPress caching.

The caching capabilities in WordPress involve different layers, methods, and tools with multiple configurations:

Server-side Caching: The server generates the cache—the technique is old, but it’s suitable for handling a lot of traffic. Examples include LiteSpeed cache, FastCGI, and other web host cache layers. Most server caching supports full-page caching. It’s reliable, but it takes a while to preload.
Object Cache: Ideal for dynamic websites or sites with high backend activity. Object caching saves database requests in RAM, reducing the number of requests—for example, Memcache and Redis.
App-Level: Cache plugins usually use PHP to serve the cache. They aren’t as fast as true server caching, but they’re effective, particularly since some offer additional features. Very fast to preload.
CDN: Caching at the edge is advancing rapidly—it used to be limited to static assets, but now it also caches entire pages.

Choosing the ideal cache setting for WordPress is essential, as making a mistake could result in your site working worse than intended.

Server-Side Caching In WordPress

In WordPress, many PHP functions and database commands are run when you receive a request. The server manages considerable queries when someone opens a page or post (depending on the template, functions, and plugins).

Some queries may take considerable time to complete if you have a large amount of data in your database. All these PHP and database requests contribute to the load time, which can be significant.

That is one reason your website has a poor Time to First Byte, even for nearby locations. However, server-level caching speeds up this procedure by caching copies of the HTML file on the server.

Results in a decrease in TTFB and reduced server resource usage, so the server only needs to serve that file. The intent is to speed up future requests by temporarily storing data.

There are different types of server-side caching for web servers, such as Nginx (FastCGI), LiteSpeed (LS Cache), Varnish, etc. Some WordPress hosting providers and cloud hosting control panels implement server caching.

LiteSpeed, Nginx, and Apache web servers — Apache | LiteSpeed | Nginx

Modern WEB hosts claim you do not need to use cache plugins since they have implemented server-level caching. Also, users can’t install caching plugins on fully managed hosts such as WP Engine, Kinsta, EasyWP, and PressLab.

The difference between static and dynamic content affects caching performance. Static content, such as graphics, stylesheets, and certain types of JavaScript, does not need to be updated frequently and is typically cached.

However, dynamic content, such as HTML elements, shopping carts, and associate profiles that change based on user behavior, is more complicated.

Approaches such as Cloudflare APO and QUIC.cloud can cache dynamic content with full-page caching. QUIC.cloud, Rocket.net, and FlyingCDN all support full-page caching, even with critical elements. Pros and cons of server-side caching:

Pros:

Improved server performance: The server spends only a minimal amount of time retrieving duplicate content. Storing query results significantly reduces the need for database search measures. Keeps your server free of clutter by caching. Cached content minimizes the workload for data-intensive content.
Improved page load speed: Cache-served pages reduce load times, providing a smooth experience even during high traffic.
Page Caching: Using server-side caching helps reduce server load on websites with dynamic content. Some hosting providers, like rocket.net, support full-page caching and significantly reduce response time on dynamic sites.
Server stability: A lower server load means fewer crashes and downtimes. Helps your website improve and handle more traffic without slowing down—capable of handling large numbers of visitors.

Cons:

Slow to regenerate: Cached pages take a long time to regenerate after being cleared at the server level. LiteSpeed cache doesn’t allow preloading.
Issues with dynamic content: Dynamic content is updated regularly in response to user interaction or in real time. Contains individualized details, such as your preferred items and profile information. This type of content doesn’t work with traditional caching methods, which treat all requests equally.
Lack of front-end optimization: Server-side caching typically caches content based on configuration settings, but cache plugins offer additional benefits by speeding up your website through front-end optimizations.
It isn’t easy: Requiring a more detailed analysis of cache settings.

Several modern web hosts, such as Rocket.net, utilize Cloudflare Enterprise for cloud caching. Additionally, Cloudflare can cache HTML pages, which works much like a server-side cache. What if that’s not enough?

In that case, it would be more advantageous to use a caching plugin, since most plugins generate HTML pages in the same way as on the server side. You can perform more front-end optimizations with cache plugins than at the server level.

Using only caching layers will only serve to cache your website, but plugins can make it more powerful and can also regenerate cache pages quickly.

When you pick WP themes, make sure they’re not too heavy, as heavy themes can cause caching issues. LiteSpeed already has caching.

If you are using Nginx, you can use FastCGI. Varnish or a caching plugin is a great option if you’re using Apache. You can use the WordPress cloud hosting control panel to access cloud hosts like Vultr. Some platforms, like SpinupWP, have built-in server caching features that act as a full-page cache.

WP Plugins For Server-Level Caching

LiteSpeed Cache: With millions of installations, it has a reputation among WordPress cache plugins. Server caching offers several benefits. Officially supporting full-page caching at EDGEs with QUIC.cloud CDN. PLUS, it’s a free plugin for LiteSpeed.
SiteGround Optimizer: This is an official SiteGround cache plugin. It supports both server-level cache and dynamic cache; however, it has several critical issues that SiteGround still needs to address.
Breeze: Designed for Cloudways’ hosting environment. It does not support dedicated server caching like LSC, but it enhances Varnish caching, which is designed for Cloudways servers.
RunCloud Hub: Settings for Redis full-page caching and FastCGI-proxy page caching if you use the RunCloud panel.
Aruba Cache: It’s only compatible with Aruba hosting.

Cache Plugins

Besides server-level caching, developers created WordPress caching solutions
for users without server access. Cache plugins typically generate HTML pages similar to those generated by the server cache. All web servers support PHP caching via plugins. However, some plugins are ideal for LiteSpeed or Apache but not for Nginx.

Some developers, however, say that, for high-traffic websites, server-level caching is more suitable than plugins because file-based caching requires more server resources to generate HTML pages.

Even if you use LiteSpeed hosting, you can use another plugin instead of LSC. Also, most plugins do not support full-page caching.

Most of the time, it does not matter whether caching is done at the file level or at the server level. If your hosting provider adds server-side caching facilities, you can still use plugins for other optimizations. For example, the FlyingPress plugin offers more than 30 optimizations beyond caching. Benefits of using the cache plugin:

Simple Caching Process: In most cases, cache plugins generate HTML pages in the same manner as server-side caching. However, cache plugins can modify the front end more effectively than server-level modifications.
Preload: This function is more convenient with plugins than server-side, as they can automatically preload (regenerate) the cache immediately or at set time intervals. Ideal if you update your website regularly.
Lazy loading: Images, videos, and even some CSS elements can be lazy-loaded by modern plugins.
CSS Optimization: Features include generating critical CSS, removing render-blocking scripts, and minifying CSS.
JavaScript Optimization: Many plugins offer features such as Defer JavaScript, Minify, and Defer inline, among others. Third-party script reductions.
Localizations: Plugins have features such as font localization, Gravatar, and other third-party resources.

There are many extra functions with plugins. Over the years, I have tried over 20 cache plugins. The good ones have valuable features, are easy to use, and keep your site undamaged. You might prefer aggressive plugins with considerable front-end optimizations if you manage only a few sites (Swift Performance, W3 Total).

You’ll obviously want a simple plugin if you manage multiple websites. Using a good WordPress CDN is also essential, as CDN caching occurs at the server level.

Object Caching

If your site has a large amount of calculated data and statistics in the admin backend, or if it constantly refreshes data, object caching is a suitable solution.

Object caching stores database results in RAM, so they don’t have to be retrieved every time. You don’t need OC if you just have a static website. Memcached is still the most popular OC add-on, but Redis is the modern one.

To Wrap Up

In the past, caching was handled solely by web servers. With so many requests, servers can become overloaded, resulting in slow response times and failures.

Server caching is ideal for sites with high traffic because it lets them handle many visitors simultaneously. Caching improves page speed and can be used even on small web servers.

However, nowadays, WordPress and other CMSs and frameworks offer many caching options, from the server to the edge. In addition, plugins have been developed for complete optimization services, including CDNs.

Use the built-in LiteSpeed plugin if your server runs LiteSpeed.
Use FastCGI or any PHP-level caching if you’re using Nginx.
If you’re using Apache, you can use Varnish or other caching mechanisms.
Cache plugins, such as WP Rocket, Swift Performance, FlyingPress, and W3 Total, can be used on any type of server.

Using the server cache is usually more efficient than using PHP. However, today’s cache plugins are more advanced and offer enhanced front-end optimization.