nyon.ch website review

About 583 KiB of JavaScript is downloaded but never used on this page. Google estimates it would make the page about 2.4 s faster on a phone.

Your mobile performance score is 31. Under 50 is Google's “poor” band: many phone visitors leave before the page is usable.

A phone's processor spends 6.5 s on main-thread work while loading, 1.9 s of it running JavaScript. Above 2 s, taps and scrolls feel sluggish.

20 long tasks block the main thread while loading, the longest for 599 ms. During a long task the page ignores taps.

The page has 2,283 HTML elements. Above 1,500, rendering and every interaction get slower on phones.

4 third-party services load with your homepage (Cookiebot, Other Google APIs/SDKs and Google CDN and others), adding 286 KiB and 356 ms of main-thread time.

8 files are served with short cache lifetimes, so returning visitors download them again (128 KiB).

Polyfills for old browsers add 42 KiB JavaScript that modern phones do not need. Google estimates it would make the page about 250 ms faster on a phone.

About 131 KiB of CSS is downloaded but never applied on this page.

1 image could be 14 KiB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen.

Critical files load one after another instead of in parallel (3 chains). Preconnecting to key origins and preloading the hero image shortens the chain.

Scripts make the browser recalculate the layout repeatedly while the page loads, which wastes processor time on phones.

Real Chrome users on phones do not pass Google's Core Web Vitals on this page (28-day field data from the Chrome UX Report (opens in a new tab)). Google uses this in ranking.

Your largest element takes 8.5 s to render on a phone. Google's threshold for “good” is 2.5 s. The largest element is the image “Salon des énergies (SIN)”.

Scripts block taps and scrolling for 2.1 s in total while the page loads. Good is under 200 ms.

Visually, the page fills in at 10.1 s (Speed Index). Good is under 3.4 s.

The page becomes fully interactive after 11.8 s. Good is under 3.8 s.

Real visitors wait 1.3 s for your server to start answering (75th percentile). Good is under 800 ms.

The first text or image appears after 2.3 s on a phone. Good is under 1.8 s.

The layout shifts by 0.144 while loading, so content jumps under the reader's thumb. Good is under 0.1.

10 images have no width and height attributes, so the layout jumps as each one loads.

Over the last 25 four-week periods to 2026-10-24, real Chrome visitors' tap response (inp) went from 97 ms to 97 ms at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Over the last 25 four-week periods to 2026-10-24, real Chrome visitors' largest content (lcp) went from 2.1 s to 2.0 s at the 75th percentile (Chrome UX Report (opens in a new tab) history).

1 image further down the page (37 KiB) download before anyone scrolls to it. Adding loading="lazy" lets the first screen load first.

By the Sustainable Web Design model, a visit to your homepage emits about 0.43 g of CO₂e: 52.1 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

2 buttons have no accessible name, so screen readers announce just “button”.

3 text elements don't have enough contrast against the background to read easily, especially outdoors on a phone.

1 element hidden from screen readers can still receive keyboard focus.

Some lists contain elements other than list items, which screen readers announce wrongly.

All page content should be contained by landmarks: 3 elements on the page fail this check, rated moderate by axe-core.

Landmarks should have a unique role or role/label/title (i.e. accessible name) combination: 2 elements on the page fail this check, rated moderate by axe-core.

Document should not have more than one banner landmark: 1 element on the page fails this check, rated moderate by axe-core.

5 form fields have no label, so screen readers announce an empty box and autofill guesses.

Alternative text of images should not be repeated as text: 1 element on the page fails this check, rated minor by axe-core.

Headings skip levels (h1 → h5), which makes the page harder to scan with a screen reader.

Your title is only 29 characters: “Ville de Nyon – Site officiel”. Between 30 and 65 characters leaves room to say what you do and for whom.

No structured data (JSON-LD), so Google can't show rich results such as your logo, ratings or FAQs.

Your meta description is 161 characters; Google truncates after about 160, so the end of your pitch is cut.

No twitter:card tag. X falls back to Open Graph, which is set, so this is minor.

The homepage links to 134 pages on nyon.ch and 5 external pages.

Your robots.txt shuts out ChatGPT (ChatGPT-User) and Perplexity (PerplexityBot). These fetch pages to answer people's questions and cite the source, so your site can't be quoted or linked in those answers.

There is no Organization (or LocalBusiness) JSON-LD, so search engines and AI assistants have no machine-readable facts about who runs the site: its name, logo, profiles and contact details.

There is no https://www.nyon.ch/llms.txt, a short Markdown guide to your key pages for AI tools (llmstxt.org). It is optional and few AI tools read it yet, so treat it as a cheap extra.

robots.txt blocks GPTBot, ClaudeBot, Google-Extended and CCBot, which collect pages to train models. That's a legitimate choice and doesn't by itself stop the site appearing in AI answers.

Your homepage links to https://www.nyon.ch/https://www.nyon.ch/demarches, which answers with an error. Visitors hit a dead end and search engines drop it.

We fetched 15 pages linked from your homepage (of 85 found) and read each the way a search engine does.

4 errors were logged to the browser console while the page loaded, for example “Cannot read properties of undefined (reading 'addEventListener')”.

Large scripts ship without source maps.

On a phone, there is no call to action on the first screen: visitors have to scroll to find out what to do next.

We found no call-to-action buttons or links (such as “Book a demo” or “Get a quote”) anywhere on the homepage.

No testimonials, customer logos, ratings or customer counts on the homepage: nothing tells a new visitor that others already trust you.

No guarantee or risk reducer (money-back, free trial, no credit card) is mentioned, which is often what tips a hesitant visitor.

The homepage carries about 578 words of visible text.

Opening the homepage sets 1 cookie (measured from a US location before any click).

Loading the homepage contacts 8 hosts run by other companies (fonts, scripts, analytics, ads), each of which sees the visitor's IP address.