rennes-sb.com website review

Google Tag Manager costs a phone 1.5 s of main-thread work and 865 KiB of downloads while your page loads. That alone is enough to make taps feel slow. Loading it after the page is usable, or only on the pages that need it, takes that off the critical path.

A phone's processor spends 7.9 s on main-thread work while loading, 4.3 s of it running JavaScript. Above 2 s, taps and scrolls feel sluggish.

8 third-party services load with your homepage (Google Tag Manager, YouTube and Facebook and others), adding 3.4 MB and 3.3 s of main-thread time.

About 1.3 MB of JavaScript is downloaded but never used on this page.

YouTube costs a phone 866 ms of main-thread work and 1.7 MB of downloads while your page loads. Loading it after the page is usable, or only on the pages that need it, takes that off the critical path.

Your mobile performance score is 58. Pages that score under 90 lose visitors before the first paint.

2 files block the first paint until they finish downloading. Deferring or inlining them could save about 650 ms.

11 files are served with short cache lifetimes, so returning visitors download them again (507 KiB).

20 long tasks block the main thread while loading, the longest for 408 ms. During a long task the page ignores taps.

Facebook costs a phone 279 ms of main-thread work and 211 KiB of downloads while your page loads. Loading it after the page is usable, or only on the pages that need it, takes that off the critical path.

docsbot.ai costs a phone 251 ms of main-thread work and 225 KiB of downloads while your page loads. Loading it after the page is usable, or only on the pages that need it, takes that off the critical path.

About 99 KiB of CSS is downloaded but never applied on this page.

2 images could be 32 KiB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen.

Polyfills for old browsers add 13 KiB JavaScript that modern phones do not need.

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.

The page becomes fully interactive after 25.3 s. Good is under 3.8 s.

Scripts block taps and scrolling for 3.1 s in total while the page loads. Good is under 200 ms.

Visually, the page fills in at 9.1 s (Speed Index). Good is under 3.4 s.

Real visitors wait 3.0 s for the largest content to appear (75th percentile). Good is under 2.5 s.

Real visitors wait 266 ms for the page to respond to a tap (75th percentile). Good is under 200 ms.

For real visitors the layout shifts by 0.13 (75th percentile). Good is under 0.1.

Over the last 25 four-week periods to 2026-10-31, real Chrome visitors' tap response (inp) went from 230 ms to 274 ms at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Real visitors see the first content after 2.2 s (75th percentile). Good is under 1.8 s.

Real visitors wait 1.4 s for your server to start answering (75th percentile). Good is under 800 ms.

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

Your homepage downloads 4.0 MB in 93 requests on a phone: scripts 3.2 MB (34), images 329 KiB (23) and HTML 177 KiB (3). Under 2 MB keeps phones on slow connections fast.

By the Sustainable Web Design model, a visit to your homepage emits about 1.12 g of CO₂e: 134.6 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

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

1 text element doesn't have enough contrast against the background to read easily, especially outdoors on a phone.

1 image has no alt text, which hurts accessibility and image search.

Landmarks should have a unique role or role/label/title (i.e. accessible name) combination: 1 element on the page fails this check, rated moderate by axe-core.

All page content should be contained by landmarks: 1 element on the page fails this check, rated moderate by axe-core.

17 visible links have no text or label, so screen readers cannot say where they go.

Elements with visible text labels do not have matching accessible names. (2 elements).

Your meta description is 169 characters; Google truncates after about 160, so the end of your pitch is cut.

Structured data found (BreadcrumbList, CollegeOrUniversity, EducationalOrganization and WebPage) but with 1 problem, for example “EducationalOrganization: sameAs is an empty list”.

18 links have no real href, so search engines can't follow them.

The homepage links to 117 pages on rennes-sb.com and 13 external pages.

Your Organization JSON-LD is missing name, url, logo, sameAs (social profiles), description and contact details. These are the facts AI assistants use to describe a business and to tell it apart from others with a similar name.

There is no https://www.rennes-sb.com/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.

https://www.rennes-sb.com/exed/formation-continue-exed-rennes, https://www.rennes-sb.com/categorie-programme/master-of-science and https://www.rennes-sb.com/exchange-programmes have no meta description, so Google writes the search snippet from whatever text it finds.

We fetched 15 pages linked from your homepage (of 91 found) and read each the way a search engine does.

10 of 27 tappable elements near the top of the page are smaller than 24 px, hard to hit with a thumb.

5 third-party cookies are set on load; browsers are restricting these, so whatever relies on them breaks.

1 image is served at too low a resolution for sharp phone screens.

Chrome logged issues while loading the page (“Cookie”).

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 637 words of visible text.

Before a visitor clicks anything, the page loads Google Ads, Google Analytics, Google Tag Manager, HubSpot and LinkedIn Insight and 1 more (measured from a US location before any click). A consent tool (Didomi) is installed; check it blocks these until visitors agree where the law requires it.

Opening the homepage sets 7 cookies, 1 of them by other companies (measured from a US location before any click).

Loading the homepage contacts 27 hosts run by other companies (fonts, scripts, analytics, ads), each of which sees the visitor's IP address.