Your site’s speed performance has a huge impact on your business success, brand perception, and bottom line— we’ve written about this more deeply here. Here, we’ve put together a shortlist of actions you or your site manager can take to speed up your WordPress site. It’s ordered from heaviest to lightest lift—heavier lifts having a larger impact on your site speed, and lighter ones having a smaller one.
Choose The Right Theme: Admittedly, this is a tough one to start off with, since switching to a new theme can be a monumental task. It could even mean a full rebuild, which might be cost-prohibitive. But a lot of speed problems with WordPress sites actually originate with the theme. It’s the foundation the entire site is built on. And just like the foundation of a house, a WordPress theme may be more or less stable and durable, resulting in better or worse performance.
We recommend compiling a list of themes that meet your design needs, looking for sites in the wild that use these themes (try a WordPress theme detector) and running that live site URL through Google PageSpeed Insights to see how well it performs. We’ve also found that some theme markets have cracked down on poor performing themes, and forced developers to build with speed in mind. Themeforest is a great example of this, and a good place to start your search for high-performing themes.
Theme optimization & caching:
Theme optimization is not for the faint of heart, and it does require some understanding of how a WordPress theme and its parts function. Luckily, there are a lot of plugins available that can automate the bulk of the work for you. We recommend WP Rocket which is an all-in-one theme compression and caching plugin.
There are several ways to optimize your theme. The first is theme compression, which comes in the form of CSS minification, HTML and .js minification, as well as image load and scripting order behavior. Minification compresses your theme code and removes any unneeded characters to make it easier for a developer to read. Image deferment and .js deferment are other ways to make your site interactable faster. (Look here for more on how interactability is measured.)
Caching, in its simplest form, is the way your site stores some information on a user’s computer after they visit your site. Caching can cut down on load speed since some of the site’s data will already have been downloaded to the user’s machine.
As we mentioned, not all themes are created equal, so the degree to which themes can be optimized varies from theme to theme.
Image Optimization + Compression: Poor image optimization is something we run into all the time, especially on websites that weren’t built by a seasoned developer or maintained with speed performance in mind. Unless you have a digital design or photography-based background it’s hard to know which image file types are best for different circumstances, especially when varying filetypes carry different metadata and file data.
For example, a .png is going to be heavier than a .jpeg because a .png is “lossless,” meaning that it’s optimized for image clarity under varying environments of compression, and carries an alpha channel allowing for image transparency. A jpeg, on the other hand, is not lossless, nor does it carry data for an alpha channel. (Imagine laying your logo on top of a color layer. It has to be a .png or .svg because those file types support alpha layers. More on .svgs later!)
Ultimately, using the correct sized photos and appropriate file types will have a huge impact on speed performance. We usually recommend Smush, which is a WordPress tool that does the bulk of image compression and filetype management for you and automatically.
Optimal hosting and leveraging a CND: Like themes, not all hosts are created equal. This is most evident in the technology a given host uses to store your site and deliver your site’s data to users. Any host worth their salt will also have a CDN (content delivery network). A CDN allows your site to distribute static access over a global network of servers. This improves performance since your data has to travel a shorter geographical distance to your end-user.