In our daily work as a web performance agency, prospects and clients contact us every day to perform audits and optimizations of their website. The initial conversations are generally of the type "my site is slow, I want it to be faster". This is true regardless of their business: e-commerce, publisher, or specialized brand, they all face the same observation of slowness, with the desire to offer a fast-loading website to their visitors.
When we dig deeper to better understand their issues, motivations, and objectives, we find quite different profiles, however.
What is a fast website, concretely?
A website is considered fast when it meets the three Core Web Vitals thresholds in the field: an LCP below 2.5 seconds, a CLS below 0.1, and an INP below 200 milliseconds. These thresholds are assessed at the 75th percentile of visits, meaning for three out of four visitors, including modest devices and slow connections.
The distinction is crucial because it shifts the focus from perception to measurable fact. A site that appears instantaneous on office fiber may fail all three thresholds on a 4G mobile. Speed is not judged on your machine, but on the actual distribution of visits, as reported by Chrome's field data.
These indicators and their measurement method are detailed in our guide to web performance and its measurement. Remember here that a speed objective is not formulated as "faster," but in quantified and third-party verifiable thresholds.
Why have a fast website?
A fast website serves three objectives at once: it converts more, because a visitor who waits abandons; it ranks better, speed being a Google ranking factor; and it costs less to serve. The three benefits accumulate without ever conflicting, which is rare in technical arbitration.
In the eyes of a majority of web publishers, generally small and medium-sized, site loading speed is primarily a matter of SEO. Their main and often only motivation is simple: gain visibility in Google's search results pages (the famous SERPs). While web performance and SEO are intimately linked thanks to the Page Experience aspect and Core Web Vitals, they thus overlook a whole part of the potential of performance optimization.
For another part of our clients, typically large corporations with an e-commerce business, it's the complete opposite! They only see the User Experience aspect, with the ingrained idea that reduced loading times will improve their commercial performance. Conversion rates, average session duration, average order value, and revenue are, in their eyes, all related to having a fast site. They are not wrong, obviously, but they also wear blinders specific to their profession.
The truth is that a fast website is an issue for SEO and UX, but much more than that. A fast site in terms of loading (FCP, LCP, Speed Index metrics...) and user interactions (TBT, INP metrics...) is essential for lasting establishment in a competitive sector. It's a quality assurance, an invisible pre-sales service, or even the best vector for your brand image. You take care of your visitors, and rest assured: they will notice!
Is your site as fast as your visitors expect?
These effects are documented by published measurements, not just by intuition. Google lists in its file on the business impact of Core Web Vitals the case of Vodafone Italy, whose 31% improvement in LCP translated into 8% additional sales, or that of Cdiscount, which recorded 6% more revenue during a Black Friday.
The bounce rate reacts just as sharply. Still according to the case studies compiled by Google, Agrofy observed 76% fewer drop-offs during loading after improving its LCP by 70%, and NDTV halved its bounce rate by halving its LCP. These orders of magnitude are not directly transferable to your site, but they indicate the scale of what's at stake.
How can we have a fast site?
Two paths lead to a fast site: integrating performance from the design stage, which is the cheapest, or optimizing an existing site, which requires measuring before acting. In both cases, performance is decided in the specifications, at the time of choosing the stack, hosting, and templates.
Having a high-performing website isn't something everyone can do. The best solution to avoid failure is to integrate speed considerations from the design of your site. By being proactive with specifications that mention web performance, you'll at least have the assurance that the issue hasn't been completely ignored. Because, unfortunately, a large majority of web design agencies still know nothing about what web performance is, let alone the ins and outs of the profession.
If the issue hasn't been anticipated, the solution is to turn to specialists, and definitely not to a generalist web agency. We're preaching to the choir here, but we regularly observe the following unfortunate reality: many agencies will tell you they can handle speed issues and have the internal resources to intervene. Some of our prospects make this choice, and return to us a few months later with bitterness, less cash flow, and the desire to finally fix their site's slowness.
Transforming a slow site into a fast one requires advanced skills, front-end developer experience, and an excellent understanding of how web browsers work. These are all qualities our teams possess, and that we make available to you as part of our performance optimization services.
On an existing site, the order of work matters as much as the work itself. The first item to examine is the server response time, as it delays everything that follows: no image optimization can compensate for a server that responds in two seconds. Cache and hosting therefore come before the front-end, never the other way around.
Next come the rendering levers: the main image of the page, whose weight and priority determine the LCP; third-party scripts, primarily responsible for interaction blocking; fonts; and the reserved dimensions for elements that load late. These four areas cover the majority of gains observed on a standard site.
This leaves the issue of ongoing maintenance. An optimized site left unmonitored will become slow again in a few months, with the pace of publications, added extensions, and stacked marketing scripts. Performance is a state to be maintained, not a project that is completed, which explains the role of monitoring in our support.
What is the cost of a fast website?
The cost of a fast website breaks down into two items: a one-time investment, for the audit and then optimizations or redesign, and a recurring cost, for hosting and maintenance, which prevent performance from degrading. The second is often forgotten in budgets, even though it is what makes the first one sustainable.
As you’ve understood, whether for a new build/redesign or for optimizing an existing site, web performance is a specialist matter. Specialists mean high added value, and high added value inevitably means cost/budget. Assume that if a freelancer or an agency gives you a commercial proposal for a few hundred euros, there’s a high chance it’s too good to be true. At Agence Web Performance, like other recognized specialists, we practice rates based on the daily rate of a senior consultant (around €900-1000/day).
To create or transform an existing site into a fast one (100% mobile PageSpeed Insights score), you will need to allocate a real budget. This is a project whose cost/benefit ratio is calculated, planned within an existing roadmap, and yields multiple returns. Combined with careful SEO work, it ensures that you meet the expectations of your visitors, search engines, as well as your partners, suppliers, etc.
The recurring cost is straightforward: our high-performance WordPress hosting offer costs €450 excl. VAT per month for an all-inclusive package, including management, maintenance, backups, and monitoring. This is the ballpark figure for a site maintained year-round, compared to the cost of a redesign necessitated by years of neglect.
The calculation is then done the other way around. An extra conversion point on a store, tens of thousands of additional page views on an editorial site, or simply visitors who no longer leave before the page loads: this is what speed brings in, and it is this amount, unique to each site, that determines if the investment is justified.
