Google has made page experience a ranking factor, and Core Web Vitals are the specific metrics it uses to assess it. For businesses running Craft CMS sites, poor scores on these metrics translate directly into lost search visibility. The frustrating part is that many of the issues that cause poor scores are entirely fixable and have been present for months or years without anyone flagging them.
The three Core Web Vitals are Largest Contentful Paint, which measures how long the main content takes to appear; Interaction to Next Paint, which measures how quickly the site responds to user input; and Cumulative Layout Shift, which measures how much the page shifts around while loading. In plain terms, that means loading fast, responding quickly, and staying still while it loads. Sites that fail on these criteria are ranked below sites that pass, all else being equal.
The most frequent causes of poor Core Web Vitals on Craft CMS sites are unoptimised images, too many third-party scripts loading in the page head, CSS and JavaScript that blocks rendering, and hosting infrastructure that is too slow for the site's requirements. Many Craft sites were built without systematic attention to these performance characteristics, particularly if they were built by an agency that prioritised delivery speed over long-term performance.
Large, unoptimised images loaded without lazy loading or appropriate sizing are responsible for the majority of Largest Contentful Paint failures on Craft CMS sites. Craft has good built-in image transformation tools, but they need to be used correctly in templates. If the site was not built with performance in mind, images are likely being served at larger sizes than necessary and without modern formats such as WebP.
Marketing tags, chat widgets, analytics libraries, and social media pixels all add weight to a page. On Craft CMS sites that have accumulated these scripts over time, the total load can be significant. Auditing which scripts are actually in use, loading them asynchronously where possible, and removing ones that are no longer needed is usually one of the faster wins in a performance review.
A Core Web Vitals improvement project on a Craft CMS site typically involves image optimisation, script audit and consolidation, caching configuration review, and in some cases template refactoring to reduce render-blocking resources. The work is measurable before and after and the results are trackable through Google Search Console. For a business-critical site where search traffic matters, it is one of the most direct investments available.
If your Craft CMS site is losing search visibility to slow Core Web Vitals scores, get in touch with Karl for a performance review.
Related Services
Most business owners have no idea what state their Craft CMS site is actually in. They know it’s working, they can add content, and the forms are submitting. Beyond that, it’s a black box. Problems can accumulate quietly over a long period before they become visible.
There’s no single answer to when you should upgrade your Craft CMS installation, but there are several clear signals that tell you it’s overdue. Most business owners don’t think about this until something goes wrong. By then, the upgrade is often more involved than it would have been if it had been handled earlier.
Most clients come to us when their site has started to feel like a risk rather than an asset. Whether the agency relationship has ended, an upgrade has been delayed, or the site has simply grown beyond what it can handle, a conversation costs nothing.
Get in touch with KarlTrusted by established businesses and growing brands across the UK
Expression 37 works with a small number of clients at any one time. These are some of them.
Karl founded Expression 37 in 2007 and has worked exclusively with ExpressionEngine and Craft CMS ever since. He does not take on work in other platforms and does not hand work to other developers. Expression 37 is deliberately small, because the kind of support that matters to clients with business-critical sites is specific to their site, not something that scales in the conventional sense. If you work with Expression 37, you work with Karl.
Find out how we workI cannot recommend Karl highly enough for his expertise and professionalism during our website upgrade. The transition from ExpressionEngine v2 to v7 was a significant undertaking, but Karl managed the entire process seamlessly, ensuring that every detail was addressed. The update of over 70 add-ons and 10 custom plugins was executed flawlessly, and the custom enhancements to our E-Commerce Store module have greatly improved our online shopping experience. The move to a more secure dedicated server has given us peace of mind regarding our site's performance and security. Karl’s dedication to our project was evident at every stage, and the final result is a modern, efficient website that truly represents our brand. Thank you for your hard work!"
Lisa Sanderson ~ Director
Graham Sanderson Interiors Ltd.