C — https://epfl.ch | BeaverCheck Audit

Site Health

Score: 74 / 100

Based on 8 categories, 0 sections

Decent speed, but optimizing further could improve engagement.

Several missing protections leave your users and data exposed.

Mostly accessible, but some users still face barriers.

Well-optimized for search — your content is discoverable.

Good server performance with room for optimization.

Mostly compliant — a few items need attention.

Good content signals with minor gaps.

Reasonable footprint with room for optimization.

How is this calculated?

The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.

Performance 25%Security 25%Accessibility 15%SEO 10%Infrastructure 10%Compliance 8%Content 5%Sustainability 2%

Weights reflect general web best practices. Individual needs may differ.

How the composite score is calculated

How you compare

Cart Functionality · 356 peers

You 74

Avg 72

At average

0 50 100

Better than 61% of Cart Functionality sites See full Cart Functionality benchmark →

WordPress · 413 peers

You 74

Avg 74

At average

0 50 100

Better than 43% of WordPress sites See full WordPress benchmark →

Top Priorities (5)

Content-Security-Policy header is missing

Security gaps expose your site and users to attacks, eroding trust.

Security › Security Headers

No Content-Security-Policy header found

Security gaps expose your site and users to attacks, eroding trust.

Security › Content Security Policy

1 button(s) with no accessible text

Accessibility issues exclude users with disabilities — up to 15% of your potential audience.

Accessibility › Link & Button Quality

1 link(s) with no accessible text

Accessibility issues exclude users with disabilities — up to 15% of your potential audience.

Accessibility › Link & Button Quality

3 image-only link(s) without alt text

Accessibility issues exclude users with disabilities — up to 15% of your potential audience.

Accessibility › Link & Button Quality

View fix priority matrix

Fix Priority Matrix

5 findings

Impact

Quick Wins

High impact, low effort — start here.

Strategic

High impact, requires investment.

Easy Improvements

Small gains, minimal effort.

Nothing in this quadrant — good news.

Deprioritize

Low impact, high effort — do last.

Nothing in this quadrant — good news.

← Low effort High effort →

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Markdown

[![BeaverCheck](https://beavercheck.com/badge?url=https%3A%2F%2Fepfl.ch)](https://beavercheck.com/results/3c82fd00-3ce0-46c9-a11f-a7ef13e3452c)

HTML

<a href="https://beavercheck.com/results/3c82fd00-3ce0-46c9-a11f-a7ef13e3452c"><img src="https://beavercheck.com/badge?url=https%3A%2F%2Fepfl.ch" alt="BeaverCheck Score"></a>

Image URL

https://beavercheck.com/badge?url=https%3A%2F%2Fepfl.ch

This badge auto-updates with your latest scan result.

What fixing these means

Your site performs reasonably well, but a few targeted fixes could meaningfully improve results. Addressing the critical issues below would have the most immediate impact on your user trust.

2 security gaps detected — browsers may warn visitors about your site.

3 accessibility issues exclude users who rely on assistive technology.

Conversion Barriers

2 critical 6 warning

8 barrier(s) likely increasing bounce by ~30%.

Speed (2)

Page takes 6.2s to load

+12% bounce

Users abandon at ~3s — you're 3.7s over the 2.5s threshold

Fix: Optimize render-blocking resources, preload the hero image, and compress images

High main-thread blocking time

+2% bounce

Page is non-interactive for 242ms after first paint

Fix: Defer third-party scripts and split large bundles

Trust (2)

No HSTS header

+1% bounce

Returning visitors are briefly exposed to downgrade attacks on first request

Fix: Set Strict-Transport-Security: max-age=31536000; includeSubDomains

No Content-Security-Policy header

+1% bounce

Higher XSS blast radius — one compromised script can exfiltrate the checkout form

Fix: Ship a reporting-only CSP first, then enforce once violations are clean

Usability (1)

Layout shifts during page load

+3% bounce

Content movement causes mis-clicks on CTAs and form fields

Fix: Add width/height to images; reserve space for late-loading embeds

Content (2)

No structured data

+2% bounce

No rich-result eligibility in Google — lower SERP CTR vs competitors with stars and prices

Fix: Add JSON-LD for your page type (Product, Article, FAQPage, LocalBusiness, …)

Content is hard to read

+2% bounce

Graduate-level reading difficulty — limits the addressable audience for product or blog pages

Fix: Shorten sentences; replace jargon with plain language; target Flesch ease ≥60

Navigation (1)

7 broken link(s) on the page

+5% bounce

Clicks land on 404s — trust drops and the session often ends

Fix: Fix or remove the broken destinations surfaced on the Content tab

Preliminary CRO audit — each barrier links to the tab with detailed analysis.

Return on Investment

CHF 715 investment → CHF 5,599/month returns + CHF 250,000 risk avoided

Payback period: < 1 month First-year ROI: +9296%

Investment

CHF 715

6h · 5 findings

Monthly returns

CHF 5,599 /mo

~CHF 67,184 / year

Conversions recovered CHF 5,598
Bandwidth savings CHF 0.38

Regulatory risk avoided

CHF 250,000

if kept compliant

nDSG/FADP CHF 250,000

Payback period

0 12mo 24mo

CHF 130 — in quick wins — start here for the fastest payback

Figures combine localized regulatory fine ceilings, search/conversion value priced against local CPC, and bandwidth waste estimates. Results depend on implementation quality and audience composition. Not legal or financial advice.

Full methodology & sources

Estimated Remediation Cost

CHF715

5.5 developer hours at CHF130/hr

Based on Switzerland rates (CHF130/hr)

Quick wins

CHF130 2 fixes in ~60 minutes

Start here for the best return on investment

Cost by category

Cost by effort level

Adjust assumptions

Custom rate

CHF /hr

Rates reflect fully-loaded developer cost including overhead

How developer rates are sourced

What Inaction Is Costing You

CHF 20,834 / month at risk

~CHF 250,005 / year if left unfixed

Compliance Risk

CHF 250,000

nDSG/FADP

No privacy policy link detected
nDSG/FADP: CHF 1,000 – CHF 250,000
Trackers detected but no cookie policy found
nDSG/FADP: CHF 1,000 – CHF 250,000
Trackers detected but no privacy policy found
nDSG/FADP: CHF 1,000 – CHF 250,000

Bandwidth Waste

CHF 0.38 /mo

5380.9 MB/mo × 0.071 CHF/GB

Optimize transfer: save ~538 KB per page load
Saves CHF 0.38/mo

Compliance figures represent the statutory maximum fine for the most severe triggered category, capped per regulation — not the sum of per-finding penalties. Based on published regulatory fine ranges. This is not legal advice.

Compliance methodology · SEO assumptions · Bandwidth model

Your performance is already good — improvements may show diminishing returns

Monthly visitors

Unique monthly visitors from your analytics

Conversion rate (%)

Purchases, signups, or key actions

Avg. order value

Optional — for revenue estimation

additional conversions/month

more engaged visitors from reduced bounce

potential monthly revenue

Current bounce (est.)

After fixes (est.)

Estimated bounce reduction

Fix 5 critical issues to capture this value

How this is calculated

Based on Google/Deloitte research ("Milliseconds Make Millions") showing a ~7% bounce rate increase per additional second of LCP above the 2.5s "Good" threshold.

Your site's LCP: → estimated after fixes.

These are estimates based on industry research — actual results vary

Bounce-rate model & assumptions

Your data stays in your browser — nothing is sent to our servers

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Lighthouse Scores

Industry-standard audits powered by Google Lighthouse.

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

Key metrics that affect user experience.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

3.87 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

6.25 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

242 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.146

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

4.35 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

11.02 s

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.

Learn more ▾

Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.

Source: Google web.dev / Lighthouse

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Request	Cache TTL	Transfer Size
/wp-content/uploads/2022/12/EPFL-vue-aerienne-Jamani-Cail...	0.0 ms	348.3 KiB
actu.epfl.ch/image/163596/1440x810.jpg	0.0 ms	312.2 KiB
www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1	0.0 ms	84.5 KiB
/wp-content/themes/wp-theme-2018/assets/js/vendors.min.js...	0.0 ms	80.3 KiB
www.epfl.ch/wp-content/uploads/2026/04/Anna-Fontcuberta-i-Morral-768x432.jpg	0.0 ms	58.9 KiB
/wp-content/themes/wp-theme-2018/assets/css/elements.min....	0.0 ms	52.3 KiB
www.epfl.ch/wp-content/uploads/2026/03/dimensions-num20-flipbook-768x432.jpg	0.0 ms	50.8 KiB
www.epfl.ch/wp-content/uploads/2026/04/David-Atienza-768x432.jpg	0.0 ms	38.7 KiB
memento.epfl.ch/image/32970/509x286.jpg	900.0 s	38.7 KiB
memento.epfl.ch/image/32754/509x286.jpg	900.0 s	36.3 KiB
memento.epfl.ch/image/32144/509x286.jpg	900.0 s	31.4 KiB
memento.epfl.ch/image/32730/509x286.jpg	900.0 s	31.1 KiB
memento.epfl.ch/image/32071/509x286.jpg	900.0 s	28.8 KiB
/wp-content/themes/wp-theme-2018/assets/js/elements.min.j...	0.0 ms	21.3 KiB
www.epfl.ch/fonts/SuisseIntl-SemiBold-WebS.woff2	0.0 ms	18.3 KiB
www.epfl.ch/fonts/SuisseIntl-Regular-WebS.woff2	0.0 ms	17.9 KiB
www.epfl.ch/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1	0.0 ms	11.3 KiB
/wp-content/plugins/enlighter/cache/enlighterjs.min.css?v...	0.0 ms	10.2 KiB
www.epfl.ch/wp-includes/js/twemoji.js?ver=6.9.4	0.0 ms	9.8 KiB
/wp-content/themes/wp-theme-2018/assets/css/vendors.min.c...	0.0 ms	7.7 KiB
/wp-content/plugins/wp-gutenberg-epfl/frontend/lib/list.m...	0.0 ms	7.2 KiB
www.epfl.ch/wp-content/uploads/2021/09/Recherche.png	0.0 ms	6.0 KiB
www.epfl.ch/wp-content/uploads/2021/09/Facultes.png	0.0 ms	4.7 KiB
www.epfl.ch/wp-content/uploads/2021/09/Education.png	0.0 ms	4.7 KiB
www.epfl.ch/wp-content/uploads/2021/09/Innovation.png	0.0 ms	4.6 KiB
www.epfl.ch/wp-includes/js/wp-emoji.js?ver=6.9.4	0.0 ms	4.4 KiB
/wp-content/plugins/flowpaper-lite-pdf-flipbook/assets/li...	0.0 ms	3.9 KiB
www.epfl.ch/wp-content/uploads/2021/09/Campus.png	0.0 ms	3.8 KiB
/wp-content/plugins/wp-gutenberg-epfl/build/style-index.c...	0.0 ms	2.1 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/theme/style.min.css?ver=1776380526	0.0 ms	2.0 KiB
www.epfl.ch/wp-content/uploads/2025/03/EPFL-logo.png	0.0 ms	1.9 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/assets/svg/epfl-logo.svg	0.0 ms	1.6 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/style.css?ver=1776380526	0.0 ms	1.4 KiB

Layout shifts occur when elements move absent any user interaction. Investigate the causes of layout shifts, such as elements being added, removed, or their fonts changing as the page loads.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:node label:Element subItemsHeading:map[key:extra] valueType:node] map[granularity:0.001 key:score label:Layout shift score subItemsHeading:map[key:cause valueType:text] valueType:numeric]]

items: [map[node:map[type:text value:Total] score:0.145757] map[node:map[boundingRect:map[bottom:866 height:312 left:0 right:412 top:554 width:412] lhId:page-10-DIV nodeLabel:Lighting up the organizers of the cell's architecture NewsResearch Scientists … path:1,HTML,1,BODY,1,DIV,7,DIV,0,DIV,2,DIV,0,MAIN,0,ARTICLE,0,DIV,3,DIV,0,DIV,0,DIV,1,DIV selector:div.container-full > div.list-group > div.fullwidth-teaser > div.fullwidth-teaser-text snippet:<div class="fullwidth-teaser-text"> type:node] score:0.145757 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:554 height:231 left:0 right:412 top:323 width:412] lhId:page-1-IMG nodeLabel:A eukaryotic cell with the centrioles shown in yellow. © iStock path:1,HTML,1,BODY,1,DIV,7,DIV,0,DIV,2,DIV,0,MAIN,0,ARTICLE,0,DIV,3,DIV,0,DIV,0,DIV,0,PICTURE,5,IMG selector:div.list-group > div.fullwidth-teaser > picture > img snippet:<img decoding="async" src="https://actu.epfl.ch/image/163596/1440x810.jpg" aria-labelledby="background-label" alt="A eukaryotic cell with the centrioles shown in yellow. © iStock"> type:node]]] type:subitems]]]

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Est Savings
www.epfl.ch/fonts/SuisseIntl-Regular-WebS.woff2	25 ms
www.epfl.ch/fonts/SuisseIntl-SemiBold-WebS.woff2	20 ms

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Resource Size	Est Savings
Vue aérienne de l'EPFL © Jamani Caillet / EPFL, 2022 `div.container-full > div.fullwidth-teaser > figure.cover > img`	/wp-content/uploads/2022/12/EPFL-vue-aerienne-Jamani-Cail...	347.2 KiB	299.6 KiB
A eukaryotic cell with the centrioles shown in yellow. © iStock `div.list-group > div.fullwidth-teaser > picture > img`	actu.epfl.ch/image/163596/1440x810.jpg	311.9 KiB	264.4 KiB
Portrait d'Anna Fontcuverta i Morral - 2026 EPFL/Mediacom - CC-BY-SA 4.0 `div.card > a.card-img-top > picture > img.img-fluid`	www.epfl.ch/wp-content/uploads/2026/04/Anna-Fontcuberta-i-Morral-768x432.jpg	57.8 KiB	17.7 KiB
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32970/509x286.jpg	38.5 KiB	14.8 KiB
Couverture du numéro 20 du magazine Dimensions. Un enfant sur un tricycle trave… `div.card > a.card-img-top > picture > img.img-fluid`	www.epfl.ch/wp-content/uploads/2026/03/dimensions-num20-flipbook-768x432.jpg	49.7 KiB	12.8 KiB
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32754/509x286.jpg	36.0 KiB	12.3 KiB
Ig Nobel `a.card > div.card-body > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32144/509x286.jpg	31.1 KiB	7.5 KiB
Finale suisse MT180. Graphisme: Laura Persat `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32730/509x286.jpg	30.8 KiB	7.1 KiB
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32071/509x286.jpg	28.5 KiB	4.8 KiB
An atom `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Recherche.png	5.0 KiB	4.1 KiB

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-1-IMG

nodeLabel: A eukaryotic cell with the centrioles shown in yellow. © iStock

path: 1,HTML,1,BODY,1,DIV,7,DIV,0,DIV,2,DIV,0,MAIN,0,ARTICLE,0,DIV,3,DIV,0,DIV,0,DIV,0,PICTURE,5,IMG

selector: div.list-group > div.fullwidth-teaser > picture > img

snippet: <img decoding="async" src="https://actu.epfl.ch/image/163596/1440x810.jpg" aria-labelledby="background-label" alt="A eukaryotic cell with the centrioles shown in yellow. © iStock">

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.

title: Preconnected origins

value: no origins were preconnected

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

value: No additional origins are good candidates for preconnecting

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size	Duration
www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1	84.5 KiB	600 ms
cdnjs.cloudflare.com/ajax/libs/jquery/3.7.1/jquery.min.js?ver=1776380526	27.5 KiB	947 ms
/wp-content/themes/wp-theme-2018/assets/css/elements.min....	52.3 KiB	600 ms
/wp-content/plugins/wp-gutenberg-epfl/frontend/lib/list.m...	7.2 KiB	150 ms
www.epfl.ch/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1	11.3 KiB
/wp-content/plugins/wp-gutenberg-epfl/build/style-index.c...	2.1 KiB
/wp-content/plugins/enlighter/cache/enlighterjs.min.css?v...	10.2 KiB	150 ms
/wp-content/plugins/flowpaper-lite-pdf-flipbook/assets/li...	3.9 KiB
/wp-content/themes/wp-theme-2018/assets/css/vendors.min.c...	7.7 KiB	150 ms
www.epfl.ch/wp-content/themes/wp-theme-2018/theme/style.min.css?ver=1776380526	2.0 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/style.css?ver=1776380526	1.4 KiB

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 2.0 s

URL	Time Spent
epfl.ch/	1.2 s
www.epfl.ch/	780 ms
www.epfl.ch/en/	0.0 ms

These are the largest layout shifts observed on the page. Each table item represents a single layout shift, and shows the element that shifted the most. Below each item are possible root causes that led to the layout shift. Some of these layout shifts may not be included in the CLS metric value due to windowing. Learn how to improve CLS

Why this matters

Performance issues directly impact user engagement and conversion rates.

Element	Layout shift score
Lighting up the organizers of the cell's architecture NewsResearch Scientists … `div.container-full > div.list-group > div.fullwidth-teaser > div.fullwidth-teaser-text`	0.146

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Diagnostics

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 320 ms 50.5 KiB

URL	Transfer Size	Est Savings
www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1	83.5 KiB	42.7 KiB
www.epfl.ch/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1	10.2 KiB	4.2 KiB
www.epfl.ch/wp-includes/js/twemoji.js?ver=6.9.4	8.8 KiB	3.7 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 320 ms 46.6 KiB

URL	Transfer Size	Est Savings
/wp-content/themes/wp-theme-2018/assets/css/elements.min....	51.3 KiB	46.6 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Multi-megabyte JavaScript bundles delay every interactive feature on the page.

Learn more ▾

This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.

Source: Google web.dev / Lighthouse

Estimated savings: 480 ms 248.3 KiB

URL	Transfer Size	Est Savings
www.googletagmanager.com/gtm.js?id=GTM-PJGBG5R	135.0 KiB	65.0 KiB
/wp-content/themes/wp-theme-2018/assets/js/vendors.min.js...	79.1 KiB	64.6 KiB
www.googletagmanager.com/gtag/js?id=G-N6BF9H5G73&cx=c&gtm=4e64h1	149.1 KiB	63.2 KiB
www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1	83.5 KiB	55.6 KiB

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Why this matters

Performance issues directly impact user engagement and conversion rates.

Category	Time Spent
Script Evaluation	758 ms
Other	682 ms
Style & Layout	395 ms
Script Parsing & Compilation	202 ms
Parse HTML & CSS	172 ms
Rendering	164 ms
Garbage Collection	28 ms

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL
Vue aérienne de l'EPFL © Jamani Caillet / EPFL, 2022 `div.container-full > div.fullwidth-teaser > figure.cover > img`	/wp-content/uploads/2022/12/EPFL-vue-aerienne-Jamani-Cail...
A eukaryotic cell with the centrioles shown in yellow. © iStock `div.list-group > div.fullwidth-teaser > picture > img`	actu.epfl.ch/image/163596/1440x810.jpg
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32754/509x286.jpg
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32071/509x286.jpg
Finale suisse MT180. Graphisme: Laura Persat `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32730/509x286.jpg
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32970/509x286.jpg
Ig Nobel `a.card > div.card-body > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32144/509x286.jpg
Logo EPFL, École polytechnique fédérale de Lausanne `div#page > header.header > a.logo > img.img-fluid`	www.epfl.ch/wp-content/themes/wp-theme-2018/assets/svg/epfl-logo.svg
Logo of the EPFL `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2025/03/EPFL-logo.png
Schools and Colleges `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Facultes.png
Rolex Learning Center `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Campus.png
A person reading a book `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Education.png
An atom `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Recherche.png
A rocket `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Innovation.png

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Optimize DOM size

●Forced reflow

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Minify CSS

●Avoids enormous network payloads Total size was 1,752 KiB

●User Timing marks and measures 5 user timings

●JavaScript execution time 0.9 s

●Avoid long main-thread tasks 10 long tasks found

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 160 ms

●Server Backend Latencies 630 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 20 ms

○INP breakdown

○Avoid non-composited animations

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Read more `div.fullwidth-teaser > div.fullwidth-teaser-text > div.fullwidth-teaser-footer > a.btn`
23.04.2026 `a.card > div.card-body > div.card-info > span.card-info-date`
18:00 `a.card > div.card-body > div.card-info > span.event-time`
20:00 `a.card > div.card-body > div.card-info > span.event-time`
Maps and directions `div.fullwidth-teaser > div.fullwidth-teaser-text > div.fullwidth-teaser-footer > a.btn`

These are opportunities to improve the legibility of your content.

Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. Learn more about accessible names.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Maps and directions `div.fullwidth-teaser > div.fullwidth-teaser-text > div.fullwidth-teaser-footer > a.btn`

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[role]`s have all required `[aria-*]` attributes

●`[role]` values are valid

●`[aria-*]` attributes have valid values

●`[aria-*]` attributes are valid and not misspelled

●Buttons have an accessible name

●Image elements have `[alt]` attributes

●Form elements have associated labels

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

●`button`, `link`, and `menuitem` elements have accessible names

●ARIA attributes are used as specified for the element's role

●Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

●`[aria-hidden="true"]` elements do not contain focusable descendents

●Elements use only permitted ARIA attributes

●Document has a `<title>` element

●`<html>` element has a `[lang]` attribute

●`<html>` element has a valid value for its `[lang]` attribute

●Links have a discernible name

●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements

●No element has a `[tabindex]` value greater than 0

●Touch targets have sufficient size and spacing.

●Heading elements appear in a sequentially-descending order

●Document has a main landmark.

●Deprecated ARIA roles were not used

●Identical links have the same purpose.

○`[accesskey]` values are unique

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

○`[role]`s are contained by their required parent element

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○ARIA IDs are unique

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○Input buttons have discernible text.

○`<input type="image">` elements have `[alt]` text

○Links are distinguishable without relying on color.

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`[lang]` attributes have a valid value

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

○Image elements do not have `[alt]` attributes that are redundant text.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

General

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Why this matters

Performance issues directly impact user engagement and conversion rates.

Source	Description
www.epfl.ch/en/	`The Content-Security-Policy directive 'worker-src' contains the keyword 'none' alongside with other source expressions. The keyword 'none' must be the only source expression in the directive value, otherwise it is ignored.`
www.epfl.ch/en/	`The Content-Security-Policy directive 'worker-src' contains the keyword 'none' alongside with other source expressions. The keyword 'none' must be the only source expression in the directive value, otherwise it is ignored.`
www.epfl.ch/en/	`The Content-Security-Policy directive 'worker-src' contains the keyword 'none' alongside with other source expressions. The keyword 'none' must be the only source expression in the directive value, otherwise it is ignored.`

●Uses HTTPS

●Avoids deprecated APIs

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Displays images with correct aspect ratio

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate DOM-based XSS with Trusted Types

●Detected JavaScript libraries

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

○Mitigate clickjacking with XFO or CSP

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

Content Best Practices

Descriptive link text helps search engines understand your content. Learn how to make links more accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Link destination	Link Text
actu.epfl.ch/news/lighting-up-the-organizers-of-the-cell-s-architect	Read more
www.epfl.ch/innovation/	Read more

Format your HTML in a way that enables crawlers to better understand your app’s content.

Crawling and Indexing

Search engines may use `href` attributes on links to crawl websites. Ensure that the `href` attribute of anchor elements links to an appropriate destination, so more pages of the site can be discovered. Learn how to make links crawlable

Why this matters

Performance issues directly impact user engagement and conversion rates.

Uncrawlable Link
EN `nav.nav-lang > ul.dropdown-menu > li > a.active`

To appear in search results, crawlers need access to your app.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Document has a meta description

●Page has successful HTTP status code

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`

○robots.txt is valid

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse. — Desktop

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

Key metrics that affect user experience. — Desktop

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

1.31 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

1.98 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

16 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

1.56 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

2.33 s

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Why this matters

Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.

Learn more ▾

Source: Google web.dev / Lighthouse

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Request	Cache TTL	Transfer Size
/wp-content/uploads/2022/12/EPFL-vue-aerienne-Jamani-Cail...	0.0 ms	348.3 KiB
actu.epfl.ch/image/163596/1440x810.jpg	0.0 ms	312.4 KiB
www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1	0.0 ms	84.6 KiB
/wp-content/themes/wp-theme-2018/assets/js/vendors.min.js...	0.0 ms	80.2 KiB
www.epfl.ch/wp-content/uploads/2026/04/Anna-Fontcuberta-i-Morral-768x432.jpg	0.0 ms	58.9 KiB
/wp-content/themes/wp-theme-2018/assets/css/elements.min....	0.0 ms	52.4 KiB
www.epfl.ch/wp-content/uploads/2026/03/dimensions-num20-flipbook-768x432.jpg	0.0 ms	50.8 KiB
www.epfl.ch/wp-content/uploads/2026/04/David-Atienza-768x432.jpg	0.0 ms	38.7 KiB
memento.epfl.ch/image/32970/509x286.jpg	900.0 s	38.8 KiB
memento.epfl.ch/image/32754/509x286.jpg	900.0 s	36.3 KiB
memento.epfl.ch/image/32144/509x286.jpg	900.0 s	31.4 KiB
memento.epfl.ch/image/32730/509x286.jpg	900.0 s	31.1 KiB
memento.epfl.ch/image/32071/509x286.jpg	900.0 s	28.8 KiB
/wp-content/themes/wp-theme-2018/assets/js/elements.min.j...	0.0 ms	21.2 KiB
www.epfl.ch/fonts/SuisseIntl-SemiBold-WebS.woff2	0.0 ms	18.3 KiB
www.epfl.ch/fonts/SuisseIntl-Regular-WebS.woff2	0.0 ms	17.9 KiB
www.epfl.ch/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1	0.0 ms	11.2 KiB
/wp-content/plugins/enlighter/cache/enlighterjs.min.css?v...	0.0 ms	10.1 KiB
www.epfl.ch/wp-includes/js/twemoji.js?ver=6.9.4	0.0 ms	9.8 KiB
/wp-content/themes/wp-theme-2018/assets/css/vendors.min.c...	0.0 ms	7.7 KiB
/wp-content/plugins/wp-gutenberg-epfl/frontend/lib/list.m...	0.0 ms	7.2 KiB
www.epfl.ch/wp-content/uploads/2021/09/Recherche.png	0.0 ms	6.0 KiB
www.epfl.ch/wp-content/uploads/2021/09/Facultes.png	0.0 ms	4.7 KiB
www.epfl.ch/wp-content/uploads/2021/09/Education.png	0.0 ms	4.7 KiB
www.epfl.ch/wp-content/uploads/2021/09/Innovation.png	0.0 ms	4.6 KiB
www.epfl.ch/wp-includes/js/wp-emoji.js?ver=6.9.4	0.0 ms	4.4 KiB
/wp-content/plugins/flowpaper-lite-pdf-flipbook/assets/li...	0.0 ms	3.9 KiB
www.epfl.ch/wp-content/uploads/2021/09/Campus.png	0.0 ms	3.8 KiB
/wp-content/plugins/wp-gutenberg-epfl/build/style-index.c...	0.0 ms	2.1 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/theme/style.min.css?ver=1776380526	0.0 ms	2.0 KiB
www.epfl.ch/wp-content/uploads/2025/03/EPFL-logo.png	0.0 ms	1.9 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/assets/svg/epfl-logo.svg	0.0 ms	1.6 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/style.css?ver=1776380526	0.0 ms	1.4 KiB

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]

items: [map[reflowTime:2.121 source:map[column:197 line:724 type:source-location url:https://www.googletagmanager.com/gtm.js?id=GTM-PJGBG5R urlProvider:network]]]

headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]

items: [map[reflowTime:84.131 source:map[type:text value:[unattributed]]] map[reflowTime:2.121 source:map[column:376 line:697 type:source-location url:https://www.googletagmanager.com/gtm.js?id=GTM-PJGBG5R urlProvider:network]]]

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Resource Size	Est Savings
A eukaryotic cell with the centrioles shown in yellow. © iStock `div.list-group > div.fullwidth-teaser > picture > img`	actu.epfl.ch/image/163596/1440x810.jpg	311.9 KiB	141.9 KiB
Vue aérienne de l'EPFL © Jamani Caillet / EPFL, 2022 `div.container-full > div.fullwidth-teaser > figure.cover > img`	/wp-content/uploads/2022/12/EPFL-vue-aerienne-Jamani-Cail...	347.2 KiB	140.1 KiB
Portrait d'Anna Fontcuverta i Morral - 2026 EPFL/Mediacom - CC-BY-SA 4.0 `div.card > a.card-img-top > picture > img.img-fluid`	www.epfl.ch/wp-content/uploads/2026/04/Anna-Fontcuberta-i-Morral-768x432.jpg	57.8 KiB	41.5 KiB
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32970/509x286.jpg	38.5 KiB	36.1 KiB
Couverture du numéro 20 du magazine Dimensions. Un enfant sur un tricycle trave… `div.card > a.card-img-top > picture > img.img-fluid`	www.epfl.ch/wp-content/uploads/2026/03/dimensions-num20-flipbook-768x432.jpg	49.7 KiB	34.8 KiB
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32754/509x286.jpg	36.0 KiB	33.6 KiB
Finale suisse MT180. Graphisme: Laura Persat `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32730/509x286.jpg	30.8 KiB	28.5 KiB
portrait de David Atienza - 2026 EPFL CC BY SA `div.card > a.card-img-top > picture > img.img-fluid`	www.epfl.ch/wp-content/uploads/2026/04/David-Atienza-768x432.jpg	37.7 KiB	26.3 KiB
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32071/509x286.jpg	28.5 KiB	26.1 KiB
Ig Nobel `a.card > div.card-body > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32144/509x286.jpg	31.1 KiB	7.5 KiB
An atom `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Recherche.png	5.0 KiB	4.1 KiB

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-0-IMG

path: 1,HTML,1,BODY,1,DIV,7,DIV,0,DIV,2,DIV,0,MAIN,0,ARTICLE,0,DIV,3,DIV,0,DIV,0,DIV,0,PICTURE,5,IMG

selector: div.list-group > div.fullwidth-teaser > picture > img

snippet: <img decoding="async" src="https://actu.epfl.ch/image/163596/1440x810.jpg" aria-labelledby="background-label" alt="A eukaryotic cell with the centrioles shown in yellow. © iStock">

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

title: Preconnected origins

value: no origins were preconnected

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

value: No additional origins are good candidates for preconnecting

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size	Duration
www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1	84.6 KiB	160 ms
www.epfl.ch/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1	11.2 KiB
cdnjs.cloudflare.com/ajax/libs/jquery/3.7.1/jquery.min.js?ver=1776380526	27.5 KiB	284 ms
/wp-content/plugins/wp-gutenberg-epfl/frontend/lib/list.m...	7.2 KiB
/wp-content/themes/wp-theme-2018/assets/css/elements.min....	52.4 KiB
/wp-content/themes/wp-theme-2018/assets/css/vendors.min.c...	7.7 KiB
/wp-content/plugins/enlighter/cache/enlighterjs.min.css?v...	10.1 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/theme/style.min.css?ver=1776380526	2.0 KiB
/wp-content/plugins/wp-gutenberg-epfl/build/style-index.c...	2.1 KiB
/wp-content/plugins/flowpaper-lite-pdf-flipbook/assets/li...	3.9 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/style.css?ver=1776380526	1.4 KiB

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Est Savings
www.epfl.ch/fonts/SuisseIntl-Regular-WebS.woff2	20 ms
www.epfl.ch/fonts/SuisseIntl-SemiBold-WebS.woff2	20 ms

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Diagnostics

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 40 ms 50.5 KiB

URL	Transfer Size	Est Savings
www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1	83.5 KiB	42.7 KiB
www.epfl.ch/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1	10.2 KiB	4.2 KiB
www.epfl.ch/wp-includes/js/twemoji.js?ver=6.9.4	8.8 KiB	3.7 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 40 ms 46.7 KiB

URL	Transfer Size	Est Savings
/wp-content/themes/wp-theme-2018/assets/css/elements.min....	51.4 KiB	46.7 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Multi-megabyte JavaScript bundles delay every interactive feature on the page.

Learn more ▾

Source: Google web.dev / Lighthouse

Estimated savings: 130 ms 248.5 KiB

URL	Transfer Size	Est Savings
www.googletagmanager.com/gtm.js?id=GTM-PJGBG5R	135.0 KiB	65.0 KiB
/wp-content/themes/wp-theme-2018/assets/js/vendors.min.js...	79.0 KiB	64.5 KiB
www.googletagmanager.com/gtag/js?id=G-N6BF9H5G73&cx=c&gtm=4e64h1	149.1 KiB	63.4 KiB
www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1	83.5 KiB	55.6 KiB

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL
Ig Nobel `a.card > div.card-body > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32144/509x286.jpg
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32754/509x286.jpg
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32071/509x286.jpg
Finale suisse MT180. Graphisme: Laura Persat `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32730/509x286.jpg
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32970/509x286.jpg
Logo EPFL, École polytechnique fédérale de Lausanne `div#page > header.header > a.logo > img.img-fluid`	www.epfl.ch/wp-content/themes/wp-theme-2018/assets/svg/epfl-logo.svg
Logo of the EPFL `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2025/03/EPFL-logo.png
Schools and Colleges `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Facultes.png
Rolex Learning Center `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Campus.png
A person reading a book `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Education.png
An atom `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Recherche.png
A rocket `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Innovation.png

More information about the performance of your application. These numbers don't directly affect the Performance score.

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 892 ms

URL	Time Spent
epfl.ch/	665 ms
www.epfl.ch/	227 ms
www.epfl.ch/en/	0.0 ms

●Time to Interactive 2.3 s

●Max Potential First Input Delay 80 ms

●Layout shift culprits

●Optimize DOM size

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Minify CSS

●Avoids enormous network payloads Total size was 1,751 KiB

●User Timing marks and measures 5 user timings

●JavaScript execution time 0.2 s

●Minimizes main-thread work 0.7 s

●Avoid long main-thread tasks 1 long task found

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 150 ms

●Server Backend Latencies 190 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 30 ms

●Avoid large layout shifts 1 layout shift found

○INP breakdown

○Avoid non-composited animations

Accessibility

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Read more sur Tech Transfer. `div.fullwidth-teaser > div.fullwidth-teaser-text > div.fullwidth-teaser-header > a.btn`
23.04.2026 `a.card > div.card-body > div.card-info > span.card-info-date`
18:00 `a.card > div.card-body > div.card-info > span.event-time`
20:00 `a.card > div.card-body > div.card-info > span.event-time`
Maps and directions `div.fullwidth-teaser > div.fullwidth-teaser-text > div.fullwidth-teaser-header > a.btn`
About `div.footer-group > div.footer-sitemap-col > button.footer-title > strong`
Organization and identity `div#collapse-footer-1 > ul.footer-links > li > a`
Associated Campuses `div#collapse-footer-1 > ul.footer-links > li > a`
Data `div#collapse-footer-1 > ul.footer-links > li > a`
Presidency `div#collapse-footer-1 > ul.footer-links > li > a`
Vice Presidencies `div#collapse-footer-1 > ul.footer-links > li > a`
Working at EPFL `div#collapse-footer-1 > ul.footer-links > li > a`
Recruiting EPFL Talents `div#collapse-footer-1 > ul.footer-links > li > a`
Equality, Diversity, Inclusion `div#collapse-footer-1 > ul.footer-links > li > a`
Respect `div#collapse-footer-1 > ul.footer-links > li > a`
Sustainability `div#collapse-footer-1 > ul.footer-links > li > a`
News & Media `div#collapse-footer-1 > ul.footer-links > li > a`
Philanthropy `div#collapse-footer-1 > ul.footer-links > li > a`
EPFL Alumni `div#collapse-footer-1 > ul.footer-links > li > a`
Education `div.footer-group > div.footer-sitemap-col > button.footer-title > strong`
Admission `div#collapse-footer-2 > ul.footer-links > li > a`
Academic Calendar `div#collapse-footer-2 > ul.footer-links > li > a`
Preparatory Year (CMS) `div#collapse-footer-2 > ul.footer-links > li > a`
Bachelor `div#collapse-footer-2 > ul.footer-links > li > a`
Master `div#collapse-footer-2 > ul.footer-links > li > a`
Doctorate `div#collapse-footer-2 > ul.footer-links > li > a`
SHS Program `div#collapse-footer-2 > ul.footer-links > li > a`
Continuing Education - Extension School `div#collapse-footer-2 > ul.footer-links > li > a`
Study Management `div#collapse-footer-2 > ul.footer-links > li > a`
International `div#collapse-footer-2 > ul.footer-links > li > a`
Teaching `div#collapse-footer-2 > ul.footer-links > li > a`
Educational Initiatives `div#collapse-footer-2 > ul.footer-links > li > a`
Education & Science Outreach `div#collapse-footer-2 > ul.footer-links > li > a`
Infrastructures Under Development `div#collapse-footer-2 > ul.footer-links > li > a`
Engaging with Society `div#collapse-footer-2 > ul.footer-links > li > a`
Research `div.footer-group > div.footer-sitemap-col > button.footer-title > strong`
Mission and Policy `div#collapse-footer-3 > ul.footer-links > li > a`
Research Domains `div#collapse-footer-3 > ul.footer-links > li > a`
EPFL Research Facilities `div#collapse-footer-3 > ul.footer-links > li > a`
Faculty Members `div#collapse-footer-3 > ul.footer-links > li > a`
Solutions 4 Sustainability - S4S `div#collapse-footer-3 > ul.footer-links > li > a`
Awards and Prizes `div#collapse-footer-3 > ul.footer-links > li > a`
Funding Opportunities `div#collapse-footer-3 > ul.footer-links > li > a`
Research Management Support `div#collapse-footer-3 > ul.footer-links > li > a`
From Lab to Market `div#collapse-footer-3 > ul.footer-links > li > a`
Research Ethics `div#collapse-footer-3 > ul.footer-links > li > a`
Research with Animals `div#collapse-footer-3 > ul.footer-links > li > a`
Open Science `div#collapse-footer-3 > ul.footer-links > li > a`
Innovation `div.footer-group > div.footer-sitemap-col > button.footer-title > strong`
Industry Collaboration `div#collapse-footer-4 > ul.footer-links > li > a`
Innovation Initiatives `div#collapse-footer-4 > ul.footer-links > li > a`
Startup Launchpad `div#collapse-footer-4 > ul.footer-links > li > a`
Campus `div.footer-group > div.footer-sitemap-col > button.footer-title > strong`
Services & Resources `div#collapse-footer-5 > ul.footer-links > li > a`
Library `div#collapse-footer-5 > ul.footer-links > li > a`
Restaurants, Shops & Hotels `div#collapse-footer-5 > ul.footer-links > li > a`
Security, Prevention & Health `div#collapse-footer-5 > ul.footer-links > li > a`
Sports `div#collapse-footer-5 > ul.footer-links > li > a`
Community & Support `div#collapse-footer-5 > ul.footer-links > li > a`
Chaplaincy `div#collapse-footer-5 > ul.footer-links > li > a`
Events `div#collapse-footer-5 > ul.footer-links > li > a`
Arts & Culture `div#collapse-footer-5 > ul.footer-links > li > a`
Associations `div#collapse-footer-5 > ul.footer-links > li > a`
Visit EPFL `div#collapse-footer-5 > ul.footer-links > li > a`
Mobility & Travel `div#collapse-footer-5 > ul.footer-links > li > a`
Schools & Colleges `footer.footer > div.footer-group > div.footer-faculties > button.footer-title`
School of Architecture, Civil & Environmental Engineering ENAC `div#collapse-fac > ul.footer-links > li > a`
ENAC `ul.footer-links > li > a > strong`
School of Basic Sciences SB `div#collapse-fac > ul.footer-links > li > a`
SB `ul.footer-links > li > a > strong`
School of Engineering STI `div#collapse-fac > ul.footer-links > li > a`
STI `ul.footer-links > li > a > strong`
School of Computer & Communication Sciences IC `div#collapse-fac > ul.footer-links > li > a`
IC `ul.footer-links > li > a > strong`
School of Life Sciences SV `div#collapse-fac > ul.footer-links > li > a`
SV `ul.footer-links > li > a > strong`
College of Management of Technology CDM `div#collapse-fac > ul.footer-links > li > a`
CDM `ul.footer-links > li > a > strong`
Practical `div.container > footer.footer > div.footer-group > p.footer-title`
Follow EPFL on social media `div.container > footer.footer > div.footer-group > p.footer-title`
Accessibility `footer.footer > div.footer-legal > div.footer-legal-links > a`
Disclaimer `footer.footer > div.footer-legal > div.footer-legal-links > a`
Privacy policy `footer.footer > div.footer-legal > div.footer-legal-links > a`
© 2025 EPFL, all rights reserved `footer.footer > div.footer-legal > div > p`

These are opportunities to improve the legibility of your content.

Names and labels

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div#page > header.header > div.dropdown > a.dropdown-toggle `div#page > header.header > div.dropdown > a.dropdown-toggle`

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. Learn more about accessible names.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Read more sur Tech Transfer. `div.fullwidth-teaser > div.fullwidth-teaser-text > div.fullwidth-teaser-header > a.btn`
Maps and directions `div.fullwidth-teaser > div.fullwidth-teaser-text > div.fullwidth-teaser-header > a.btn`

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[role]`s have all required `[aria-*]` attributes

●`[role]` values are valid

●`[aria-*]` attributes have valid values

●`[aria-*]` attributes are valid and not misspelled

●Buttons have an accessible name

●Image elements have `[alt]` attributes

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

●`button`, `link`, and `menuitem` elements have accessible names

●ARIA attributes are used as specified for the element's role

●Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

●`[aria-hidden="true"]` elements do not contain focusable descendents

●Elements use only permitted ARIA attributes

●Document has a `<title>` element

●`<html>` element has a `[lang]` attribute

●`<html>` element has a valid value for its `[lang]` attribute

●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements

●No element has a `[tabindex]` value greater than 0

●Touch targets have sufficient size and spacing.

●Heading elements appear in a sequentially-descending order

●Document has a main landmark.

●Deprecated ARIA roles were not used

●Identical links have the same purpose.

○`[accesskey]` values are unique

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

○`[role]`s are contained by their required parent element

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○ARIA IDs are unique

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○Input buttons have discernible text.

○`<input type="image">` elements have `[alt]` text

○Form elements have associated labels

○Links are distinguishable without relying on color.

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`[lang]` attributes have a valid value

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

○Image elements do not have `[alt]` attributes that are redundant text.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

General

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Why this matters

Performance issues directly impact user engagement and conversion rates.

Source	Description
www.epfl.ch/en/	`The Content-Security-Policy directive 'worker-src' contains the keyword 'none' alongside with other source expressions. The keyword 'none' must be the only source expression in the directive value, otherwise it is ignored.`
www.epfl.ch/en/	`The Content-Security-Policy directive 'worker-src' contains the keyword 'none' alongside with other source expressions. The keyword 'none' must be the only source expression in the directive value, otherwise it is ignored.`
www.epfl.ch/en/	`The Content-Security-Policy directive 'worker-src' contains the keyword 'none' alongside with other source expressions. The keyword 'none' must be the only source expression in the directive value, otherwise it is ignored.`

●Uses HTTPS

●Avoids deprecated APIs

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Displays images with correct aspect ratio

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate DOM-based XSS with Trusted Types

●Detected JavaScript libraries

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

○Mitigate clickjacking with XFO or CSP

SEO

Content Best Practices

Descriptive link text helps search engines understand your content. Learn how to make links more accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Link destination	Link Text
actu.epfl.ch/news/lighting-up-the-organizers-of-the-cell-s-architect	Read more
www.epfl.ch/innovation/	Read more

Format your HTML in a way that enables crawlers to better understand your app’s content.

Crawling and Indexing

Why this matters

Performance issues directly impact user engagement and conversion rates.

Uncrawlable Link
EN `nav.nav-lang > ul.dropdown-menu > li > a.active`

To appear in search results, crawlers need access to your app.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Document has a meta description

●Page has successful HTTP status code

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`

○robots.txt is valid

Results for https://epfl.ch

Site Health

How you compare

Top Priorities (5)

Fix Priority Matrix

Quick Wins

Strategic

Easy Improvements

Deprioritize

What fixing these means

Conversion Barriers

Speed (2)

Trust (2)

Usability (1)

Content (2)

Navigation (1)

Return on Investment

Investment

Monthly returns

Regulatory risk avoided

Payback period

Estimated Remediation Cost

Cost by category

Cost by effort level

What Inaction Is Costing You

Compliance Risk

Bandwidth Waste

Lighthouse Scores

Core Web Vitals

Detailed Report

Performance

Insights

Diagnostics

Accessibility

Contrast

Best Practices

General

SEO

Content Best Practices

Crawling and Indexing

Lighthouse Scores

Core Web Vitals

Detailed Report

Performance

Insights

Diagnostics

Accessibility

Contrast

Names and labels

Best Practices

General

SEO

Content Best Practices

Crawling and Indexing

Keyboard Shortcuts