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Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
77
GRADE
C
FIX
4
REVIEW
3
PASS
6
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
86
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
93
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
83
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

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

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
15
6 PASS 3 REVIEW 4 FIX
D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (1.7 MiB of 1.7 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
D
JS Bundles
Action
13 scripts, 249 KB unused
FIX
13 scripts, 249 KB unused
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-PJG...: 65 KB unused (48%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.epfl.ch/wp-content/themes/wp-theme-201...: 65 KB unused (82%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=G-N6BF...: 63 KB unused (42%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.epfl.ch/wp-includes/js/jquery/jquery.j...: 56 KB unused (67%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.epfl.ch/wp-includes/js/jquery/jquery.j...: unminified — 43 KB could be saved
Info::
Total unused JavaScript: 249 KB
249 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtm.js?id=GTM-PJGBG5R135 KB65 KB (48%)✓3rd
https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/js/vendors.min.js?ver=177638052680 KB65 KB (82%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-N6BF9H5G73&cx=c&gtm=4e64h1149 KB63 KB (42%)✓3rd
https://www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.185 KB56 KB (67%)✗3rd
https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/js/elements.min.js?ver=177638052621 KB—✓3rd
https://cdnjs.cloudflare.com/ajax/libs/jquery/3.7.1/jquery.min.js?ver=177638052627 KB—✓3rd
https://www.epfl.ch/wp-content/plugins/flowpaper-lite-pdf-flipbook/assets/lity/lity.min.js4 KB—✓3rd
https://umami.fsd.epfl.ch/script.js2 KB—✓3rd
https://www.epfl.ch/wp-content/plugins/wp-gutenberg-epfl/frontend/lib/list.min.js?ver=1.57 KB—✓3rd
blob:https://www.epfl.ch/1a20f4c0-ada3-4def-a640-49ce044d812c-0 KB—✓3rd

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

D
Page Weight Inventory
Action
50 resources · 1.7 MB · 249 KB savings available
FIX
50 resources · 1.7 MB · 249 KB savings available
Warning::
Page weight 727 KB over 1MB target
Got: 1.7 MB Expected: ≤ 1 MB
Info::
~249 KB of savings available
Warning::
49 third-party resources (100% of weight)
Info::
2 resources over 200KB
50 resources · 1.7 MiB · 49 third-party 727.2 KiB over 1MB target
Image 62% · 1.1 MiB
JavaScript 31% · 536.5 KiB
CSS 4% · 75.7 KiB
Font 2% · 36.2 KiB
Document 1% · 19.7 KiB
Other 0% · 2.7 KiB

~248.5 KiB of savings available

Remove unused JavaScript: 248.5 KiB
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Page Weight Budget
Action
1.7 MB transferred, 50 requests
REVIEW
1.7 MB transferred, 50 requests
Info::
Page weighs 3.3 MB (1.7 MB transferred)
Warning::
JavaScript is 537 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 537 KB
Info::
50 HTTP requests
Info::
Estimated 0.36 g CO2 per page load
1.7 MB / 2.4 MB budget
1.7 MB transferred
50 requests
0.36 g CO2 per page load
Images 1004.6 KiB 57%
JavaScript 536.5 KiB 31%
CSS 75.7 KiB 4%
Other 74.0 KiB 4%
Fonts 36.2 KiB 2%
HTML 18.4 KiB 1%
Other 3.2 KiB 0%
Other 1.4 KiB 0%
Other 1.3 KiB 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Approaching limit

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

Source: web.dev

C
Image Optimization
Action
19 images, 0 KB saveable
REVIEW
19 images, 0 KB saveable
Warning::
https://www.epfl.ch/wp-content/uploads/2021/09/Fac... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.epfl.ch/wp-content/uploads/2021/09/Inn... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.epfl.ch/wp-content/uploads/2025/03/EPF... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.epfl.ch/wp-content/uploads/2021/09/Cam... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://memento.epfl.ch/image/32144/509x286.jpg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://memento.epfl.ch/image/32970/509x286.jpg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://memento.epfl.ch/image/32754/509x286.jpg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://memento.epfl.ch/image/32730/509x286.jpg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.epfl.ch/wp-content/themes/wp-theme-201... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://memento.epfl.ch/image/32071/509x286.jpg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.epfl.ch/wp-content/uploads/2021/09/Edu... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.epfl.ch/wp-content/uploads/2021/09/Rec... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
19 images 1005 KB
0 oversized -0 KB
19 legacy format
12 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
JS Execution Cost
490ms total JS execution
PASS
490ms total JS execution
Info::
https://www.epfl.ch/en/: 201ms CPU time
Info::
Unattributable: 128ms CPU time
Info::
https://www.googletagmanager.com/gtag/js?id=G-N6BF...: 86ms CPU time
Info::
https://www.googletagmanager.com/gtm.js?id=GTM-PJG...: 76ms CPU time
Warning::
Third-party scripts: 490ms (100% of total)

Main Thread Breakdown

Script Evaluation 35% Other 24% Style & Layout 21% Script Parsing & Compilation 9% Parse HTML & CSS 7%
ScriptTotalScriptingParse/CompileParty
https://www.epfl.ch/en/201ms3ms1ms3rd
Unattributable128ms4ms0ms3rd
https://www.googletagmanager.com/gtag/js?id=G-N6BF9H5G73&cx=c&gtm=4e64h186ms69ms14ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-PJGBG5R76ms61ms12ms3rd
A+
Font Loading
2 fonts (36 KB)
PASS
2 fonts (36 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

36 KB total

Render-blocking

0

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s 1.5 s 2.0 s FCP 1.3 s LCP 2.0 shttps://www.epfl.ch/fonts/SuisseIntl-Regular-WebS.woff2SuisseIntl-Regular-WebS... https://www.epfl.ch/fonts/SuisseIntl-Regular-WebS.woff2 — 17.9 KiB — 24 ms — font-display: swaphttps://www.epfl.ch/fonts/SuisseIntl-SemiBold-WebS.woff2SuisseIntl-SemiBold-Web... https://www.epfl.ch/fonts/SuisseIntl-SemiBold-WebS.woff2 — 18.3 KiB — 23 ms — font-display: swap
SuisseIntl-Regular-WebS... woff2 swap
Size 18 KB
Load time 24 ms
Start 1.2 s
Risk FOUT — text flashes from fallback to web font
SuisseIntl-SemiBold-Web... woff2 swap
Size 18 KB
Load time 23 ms
Start 1.2 s
Risk FOUT — text flashes from fallback to web font
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
Network Waterfall
50 requests over 2243ms
INFO
0 ms 500 ms 1.0 s 1.5 s 2.0 s FCP 1.3 s LCP 2.0 shttps://epfl.ch// https://epfl.ch/ — 301 — 237 B — 627 ms — h2https://www.epfl.ch/www.epfl.ch/ https://www.epfl.ch/ — 302 — 1.1 KiB — 243 ms — h2https://www.epfl.ch/en/www.epfl.ch/en/ https://www.epfl.ch/en/ — 200 — 18.4 KiB — 31 ms — h2https://www.epfl.ch/wp-content/plugins/wp-gutenberg-epfl/build/style-index.css?ver=1776380665www.epfl.ch/wp-content/plugins/wp-g... https://www.epfl.ch/wp-content/plugins/wp-gutenberg-epfl/build/style-index.css?ver=1776380665 — 200 — 2.1 KiB — 46 ms — h3https://www.epfl.ch/wp-content/themes/wp-theme-2018/style.css?ver=1776380526www.epfl.ch/wp-content/themes/wp-th... https://www.epfl.ch/wp-content/themes/wp-theme-2018/style.css?ver=1776380526 — 200 — 1.4 KiB — 35 ms — h3https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/css/vendors.min.css?ver=1776380526www.epfl.ch/wp-content/themes/wp-th... https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/css/vendors.min.css?ver=1776380526 — 200 — 7.7 KiB — 59 ms — h3https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/css/elements.min.css?ver=1776380526www.epfl.ch/wp-content/themes/wp-th... https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/css/elements.min.css?ver=1776380526 — 200 — 52.4 KiB — 70 ms — h3https://www.epfl.ch/wp-content/themes/wp-theme-2018/theme/style.min.css?ver=1776380526www.epfl.ch/wp-content/themes/wp-th... https://www.epfl.ch/wp-content/themes/wp-theme-2018/theme/style.min.css?ver=1776380526 — 200 — 2.0 KiB — 53 ms — h3https://www.epfl.ch/wp-content/plugins/enlighter/cache/enlighterjs.min.css?ver=nOru9GX9Bgee7Xgwww.epfl.ch/wp-content/plugins/enli... https://www.epfl.ch/wp-content/plugins/enlighter/cache/enlighterjs.min.css?ver=nOru9GX9Bgee7Xg — 200 — 10.1 KiB — 55 ms — h3https://www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1www.epfl.ch/wp-includes/js/jquery/j... https://www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1 — 200 — 84.6 KiB — 70 ms — h3https://www.epfl.ch/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1www.epfl.ch/wp-includes/js/jquery/j... https://www.epfl.ch/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1 — 200 — 11.2 KiB — 67 ms — h3https://www.epfl.ch/wp-content/plugins/wp-gutenberg-epfl/frontend/lib/list.min.js?ver=1.5www.epfl.ch/wp-content/plugins/wp-g... https://www.epfl.ch/wp-content/plugins/wp-gutenberg-epfl/frontend/lib/list.min.js?ver=1.5 — 200 — 7.2 KiB — 65 ms — h3https://www.epfl.ch/wp-content/plugins/flowpaper-lite-pdf-flipbook/assets/lity/lity.min.jswww.epfl.ch/wp-content/plugins/flow... https://www.epfl.ch/wp-content/plugins/flowpaper-lite-pdf-flipbook/assets/lity/lity.min.js — 200 — 3.9 KiB — 39 ms — h3https://cdnjs.cloudflare.com/ajax/libs/jquery/3.7.1/jquery.min.js?ver=1776380526cdnjs.cloudflare.com/ajax/libs/jque... https://cdnjs.cloudflare.com/ajax/libs/jquery/3.7.1/jquery.min.js?ver=1776380526 — 200 — 27.5 KiB — 63 ms — h3https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/svg/epfl-logo.svgwww.epfl.ch/wp-content/themes/wp-th... https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/svg/epfl-logo.svg — 200 — 1.6 KiB — 62 ms — h3https://actu.epfl.ch/image/163596/1440x810.jpgactu.epfl.ch/image/163596/1440x810.... https://actu.epfl.ch/image/163596/1440x810.jpg — 200 — 312.4 KiB — 252 ms — h2https://www.epfl.ch/wp-content/uploads/2026/04/David-Atienza-768x432.jpgwww.epfl.ch/wp-content/uploads/2026... https://www.epfl.ch/wp-content/uploads/2026/04/David-Atienza-768x432.jpg — 200 — 38.7 KiB — 20 ms — h3https://www.epfl.ch/wp-content/uploads/2026/04/Anna-Fontcuberta-i-Morral-768x432.jpgwww.epfl.ch/wp-content/uploads/2026... https://www.epfl.ch/wp-content/uploads/2026/04/Anna-Fontcuberta-i-Morral-768x432.jpg — 200 — 58.9 KiB — 18 ms — h3https://www.epfl.ch/wp-content/uploads/2025/03/EPFL-logo.pngwww.epfl.ch/wp-content/uploads/2025... https://www.epfl.ch/wp-content/uploads/2025/03/EPFL-logo.png — 200 — 1.9 KiB — 16 ms — h3https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/js/vendors.min.js?ver=1776380526www.epfl.ch/wp-content/themes/wp-th... https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/js/vendors.min.js?ver=1776380526 — 200 — 80.2 KiB — 74 ms — h3https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/js/elements.min.js?ver=1776380526www.epfl.ch/wp-content/themes/wp-th... https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/js/elements.min.js?ver=1776380526 — 200 — 21.2 KiB — 56 ms — h3https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/favicons/site.webmanifestwww.epfl.ch/wp-content/themes/wp-th... https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/favicons/site.webmanifest — 200 — 1.3 KiB — 58 ms — h3https://umami.fsd.epfl.ch/script.jsumami.fsd.epfl.ch/script.js https://umami.fsd.epfl.ch/script.js — 200 — 2.0 KiB — 201 ms — h2https://www.epfl.ch/wp-content/uploads/2021/09/Facultes.pngwww.epfl.ch/wp-content/uploads/2021... https://www.epfl.ch/wp-content/uploads/2021/09/Facultes.png — 200 — 4.7 KiB — 47 ms — h3https://www.epfl.ch/wp-content/uploads/2021/09/Campus.pngwww.epfl.ch/wp-content/uploads/2021... https://www.epfl.ch/wp-content/uploads/2021/09/Campus.png — 200 — 3.8 KiB — 46 ms — h3https://memento.epfl.ch/image/32144/509x286.jpgmemento.epfl.ch/image/32144/509x286... https://memento.epfl.ch/image/32144/509x286.jpg — 200 — 31.4 KiB — 227 ms — h3https://memento.epfl.ch/image/32754/509x286.jpgmemento.epfl.ch/image/32754/509x286... https://memento.epfl.ch/image/32754/509x286.jpg — 200 — 36.3 KiB — 222 ms — h3https://memento.epfl.ch/image/32071/509x286.jpgmemento.epfl.ch/image/32071/509x286... https://memento.epfl.ch/image/32071/509x286.jpg — 200 — 28.8 KiB — 223 ms — h3https://memento.epfl.ch/image/32730/509x286.jpgmemento.epfl.ch/image/32730/509x286... https://memento.epfl.ch/image/32730/509x286.jpg — 200 — 31.1 KiB — 227 ms — h3https://memento.epfl.ch/image/32970/509x286.jpgmemento.epfl.ch/image/32970/509x286... https://memento.epfl.ch/image/32970/509x286.jpg — 200 — 38.8 KiB — 226 ms — h3
0 ms 500 ms 1.0 s 1.5 s 2.0 s FCP 1.3 s LCP 2.0 shttps://epfl.ch// https://epfl.ch/ — 301 — 237 B — 627 ms — h2https://www.epfl.ch/www.epfl.ch/ https://www.epfl.ch/ — 302 — 1.1 KiB — 243 ms — h2https://www.epfl.ch/en/www.epfl.ch/en/ https://www.epfl.ch/en/ — 200 — 18.4 KiB — 31 ms — h2https://www.epfl.ch/wp-content/plugins/wp-gutenberg-epfl/build/style-index.css?ver=1776380665www.epfl.ch/wp-content/plugins/wp-g... https://www.epfl.ch/wp-content/plugins/wp-gutenberg-epfl/build/style-index.css?ver=1776380665 — 200 — 2.1 KiB — 46 ms — h3https://www.epfl.ch/wp-content/themes/wp-theme-2018/style.css?ver=1776380526www.epfl.ch/wp-content/themes/wp-th... https://www.epfl.ch/wp-content/themes/wp-theme-2018/style.css?ver=1776380526 — 200 — 1.4 KiB — 35 ms — h3https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/css/vendors.min.css?ver=1776380526www.epfl.ch/wp-content/themes/wp-th... https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/css/vendors.min.css?ver=1776380526 — 200 — 7.7 KiB — 59 ms — h3https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/css/elements.min.css?ver=1776380526www.epfl.ch/wp-content/themes/wp-th... https://www.epfl.ch/wp-content/themes/wp-theme-2018/assets/css/elements.min.css?ver=1776380526 — 200 — 52.4 KiB — 70 ms — h3https://www.epfl.ch/wp-content/themes/wp-theme-2018/theme/style.min.css?ver=1776380526www.epfl.ch/wp-content/themes/wp-th... https://www.epfl.ch/wp-content/themes/wp-theme-2018/theme/style.min.css?ver=1776380526 — 200 — 2.0 KiB — 53 ms — h3https://www.epfl.ch/wp-content/plugins/enlighter/cache/enlighterjs.min.css?ver=nOru9GX9Bgee7Xgwww.epfl.ch/wp-content/plugins/enli... https://www.epfl.ch/wp-content/plugins/enlighter/cache/enlighterjs.min.css?ver=nOru9GX9Bgee7Xg — 200 — 10.1 KiB — 55 ms — h3https://www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1www.epfl.ch/wp-includes/js/jquery/j... https://www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1 — 200 — 84.6 KiB — 70 ms — 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HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 490ms · 303KB · CHF2/mo
www.epfl.ch
Other
Costly
Execution 201ms
Transfer 18 KB
Monthly Cost CHF1/mo
Unattributable
Other
Optional
Execution 128ms
Transfer 0 KB
Monthly Cost CHF1/mo
Google Tag Manager
Tag Manager
Optional
Execution 86ms
Transfer 149 KB
Unused 42%
Monthly Cost CHF0/mo
Google Tag Manager
Tag Manager
Optional
Execution 76ms
Transfer 135 KB
Unused 48%
Monthly Cost CHF0/mo

These scripts may cost more than they're worth

  • www.epfl.ch adds 201ms and costs ~CHF1/month

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

www.epfl.ch takes 201ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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