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Performance

· 18 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
90
GRADE
A
FIX
0
REVIEW
5
PASS
10
INFO
3

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

Mobile Desktop
79
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.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
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.

1.66 s

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

5.44 s

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

28 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.

2.34 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.

5.71 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
18
10 PASS 5 REVIEW
C
Image Optimization
Action
17 images, 0 KB saveable
REVIEW
17 images, 0 KB saveable
Warning::
https://linuxfr.org/images/sections/15.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://linuxfr.org/images/sections/89.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://linuxfr.org/images/logos/anim.gif is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://img.linuxfr.org/img/68747470733a2f2f777777... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://linuxfr.org/images/sections/84.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://img.linuxfr.org/img/68747470733a2f2f777777... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://linuxfr.org/images/sections/22.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://linuxfr.org/images/sections/19.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://linuxfr.org/images/sections/9.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://linuxfr.org/images/sections/17.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://linuxfr.org/images/sections/27.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://linuxfr.org/images/sections/46.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://img.linuxfr.org/img/68747470733a2f2f616469... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
17 images 317 KB
0 oversized -0 KB
16 legacy format
13 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

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
JS Execution Cost
Action
1017ms total JS execution
REVIEW
1017ms total JS execution
Warning::
https://linuxfr.org/: 658ms CPU time
Info::
Unattributable: 228ms CPU time
Info::
https://linuxfr.org/assets/application-ea18d32113d...: 131ms CPU time
Info::
Third-party scripts: 228ms (22% of total)

Main Thread Breakdown

Style & Layout 37% Other 30% Rendering 17% Script Evaluation 11% Parse HTML & CSS 4%
ScriptTotalScriptingParse/CompileParty
https://linuxfr.org/658ms5ms1ms1st
Unattributable228ms8ms0ms3rd
https://linuxfr.org/assets/application-ea18d32113d34928f73c40c3e7e4aee7b5cc739bee5f9f08fb03d30b00343c90.js131ms95ms19ms1st
B
JS Bundles
1 scripts, 98 KB unused
REVIEW
1 scripts, 98 KB unused
Warning::
https://linuxfr.org/assets/application-ea18d32113d...: 98 KB unused (69%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 98 KB
98 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://linuxfr.org/assets/application-ea18d32113d34928f73c40c3e7e4aee7b5cc739bee5f9f08fb03d30b00343c90.js144 KB98 KB (69%)✓1st

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

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

Green Hosting

No green hosting detected

B
HTTP Caching
max-age=0, private, must-revalidate
REVIEW
max-age=0, private, must-revalidate
Info::
Cache-Control header is set
Got: max-age=0, private, must-revalidate
Info::
ETag present — enables conditional (304) responses
Cache-Control

max-age=0, private, must-revalidate

DirectiveValueMeaning
max-age0Cache for 0 seconds
private—Only browser cache, not CDN/proxy
must-revalidate—Must recheck with server after expiry
A
Page Weight Budget
838 KB transferred, 25 requests
PASS
838 KB transferred, 25 requests
Info::
Page weighs 886 KB (838 KB transferred)
Info::
Fonts are 281 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 281 KB
Info::
25 HTTP requests
Info::
Estimated 0.17 g CO2 per page load
838 KB / 2.4 MB budget
838 KB transferred
25 requests
0.17 g CO2 per page load
Images 316.8 KiB 38%
Fonts 281.5 KiB 34%
JavaScript 143.6 KiB 17%
CSS 75.6 KiB 9%
HTML 18.8 KiB 2%
Other 2.0 KiB 0%
0 2.4 MB 4.9 MB
Under budget

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).

Source: web.dev font loading

A
Third-Party Impact
31% third-party, 0 ms blocking
PASS
31% third-party, 0 ms blocking
Info::
Third-party code accounts for 31% of page weight (260.2 KiB of 838.4 KiB)
Info::
Third-party blocking time is low (0 ms)
69%
31%
First-party Third-party
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+
Font Loading
2 fonts (281 KB)
PASS
2 fonts (281 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

281 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 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s FCP 1.7 s LCP 5.4 shttps://linuxfr.org/fonts/Lato-Regular.woff2Lato-Regular.woff2 https://linuxfr.org/fonts/Lato-Regular.woff2 — 178.9 KiB — 472 ms — font-display: swaphttps://linuxfr.org/fonts/Merriweather-Regular.woff2Merriweather-Regular.woff2 https://linuxfr.org/fonts/Merriweather-Regular.woff2 — 102.6 KiB — 480 ms — font-display: swap
Lato-Regular.woff2 woff2 swap
Size 179 KB
Load time 472 ms
Start 846 ms
Risk FOUT — text flashes from fallback to web font
  • Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
Merriweather-Regular.woff2 woff2 swap
Size 103 KB
Load time 480 ms
Start 846 ms
Risk FOUT — text flashes from fallback to web font
  • Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
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)

Fixing the unchecked items could save ~141 KB and ~282 ms

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
A+
Page Weight Inventory
25 resources · 838 KB · 98 KB savings available
PASS
25 resources · 838 KB · 98 KB savings available
Info::
Within 1MB page-weight target
Got: 838 KB
Info::
~98 KB of savings available
Info::
6 third-party resources (31% of weight)
25 resources · 838.4 KiB · 6 third-party Within 1MB page-weight target
Image 38% · 318.8 KiB
Font 34% · 281.5 KiB
JavaScript 17% · 143.6 KiB
CSS 9% · 75.6 KiB
Document 2% · 18.8 KiB

~98.5 KiB of savings available

Remove unused JavaScript: 98.5 KiB
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
Network Waterfall
25 requests over 1632ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s FCP 1.7 s LCP 5.4 shttps://linuxfr.org// https://linuxfr.org/ — 200 — 18.8 KiB — 541 ms — h2https://linuxfr.org/assets/application-c62860ac5f0522aa8cd2bb9e4162050f55f364b368cc24537d6994c64f0efa8e.css/assets/application-c62860ac5f0522a... https://linuxfr.org/assets/application-c62860ac5f0522aa8cd2bb9e4162050f55f364b368cc24537d6994c64f0efa8e.css — 200 — 75.6 KiB — 213 ms — h2https://linuxfr.org/images/sections/46.png/images/sections/46.png https://linuxfr.org/images/sections/46.png — 200 — 2.4 KiB — 214 ms — h2https://img.linuxfr.org/img/68747470733a2f2f616469657577696e646f77732e617072696c2e6f72672f6c6f63616c2f63616368652d7669676e65747465732f4c36373278483136382f62616e6e696572655f61646965755f77696e646f77732d64633463312e706e673f31373539323135333038/banniere_adieu_windows-dc4c1.png?1759215308img.linuxfr.org/img/68747470733a2f2... https://img.linuxfr.org/img/68747470733a2f2f616469657577696e646f77732e617072696c2e6f72672f6c6f63616c2f63616368652d7669676e65747465732f4c36373278483136382f62616e6e696572655f61646965755f77696e646f77732d64633463312e706e673f31373539323135333038/banniere_adieu_windows-dc4c1.png?1759215308 — 200 — 116.3 KiB — 553 ms — h2https://linuxfr.org/images/sections/22.png/images/sections/22.png https://linuxfr.org/images/sections/22.png — 200 — 3.1 KiB — 210 ms — h2https://linuxfr.org/images/sections/15.png/images/sections/15.png https://linuxfr.org/images/sections/15.png — 200 — 1.3 KiB — 255 ms — h2https://linuxfr.org/images/sections/9.png/images/sections/9.png https://linuxfr.org/images/sections/9.png — 200 — 3.0 KiB — 284 ms — h2https://linuxfr.org/assets/application-ea18d32113d34928f73c40c3e7e4aee7b5cc739bee5f9f08fb03d30b00343c90.js/assets/application-ea18d32113d3492... https://linuxfr.org/assets/application-ea18d32113d34928f73c40c3e7e4aee7b5cc739bee5f9f08fb03d30b00343c90.js — 200 — 143.6 KiB — 361 ms — h2https://img.linuxfr.org/img/68747470733a2f2f7777772e6c696272652d656e2d666574652e6f72672f494d472f706e672f617070656c2d7765622d3438367838302d6c696272652d656e2d666574652d323032362e706e67/appel-web-486x80-libre-en-fete-2026.pngimg.linuxfr.org/img/68747470733a2f2... https://img.linuxfr.org/img/68747470733a2f2f7777772e6c696272652d656e2d666574652e6f72672f494d472f706e672f617070656c2d7765622d3438367838302d6c696272652d656e2d666574652d323032362e706e67/appel-web-486x80-libre-en-fete-2026.png — 200 — 41.6 KiB — 620 ms — h2https://linuxfr.org/images/sections/17.png/images/sections/17.png https://linuxfr.org/images/sections/17.png — 200 — 1.8 KiB — 364 ms — h2https://linuxfr.org/images/sections/89.png/images/sections/89.png https://linuxfr.org/images/sections/89.png — 200 — 4.1 KiB — 385 ms — h2https://linuxfr.org/images/sections/84.png/images/sections/84.png https://linuxfr.org/images/sections/84.png — 200 — 2.7 KiB — 420 ms — h2https://img.linuxfr.org/img/68747470733a2f2f7777772e70726f6a6574732d6c69627265732e6f72672f77702d636f6e74656e742f75706c6f6164732f323032362f30342f50726f6a6574732d4c6962726573785669652d7072697665652d373836783431332d312e706e67/Projets-LibresxVie-privee-786x413-1.pngimg.linuxfr.org/img/68747470733a2f2... https://img.linuxfr.org/img/68747470733a2f2f7777772e70726f6a6574732d6c69627265732e6f72672f77702d636f6e74656e742f75706c6f6164732f323032362f30342f50726f6a6574732d4c6962726573785669652d7072697665652d373836783431332d312e706e67/Projets-LibresxVie-privee-786x413-1.png — 200 — 102.2 KiB — 867 ms — h2https://linuxfr.org/images/sections/27.png/images/sections/27.png https://linuxfr.org/images/sections/27.png — 200 — 5.8 KiB — 443 ms — h2https://linuxfr.org/images/logos/anim.gif/images/logos/anim.gif https://linuxfr.org/images/logos/anim.gif — 200 — 10.2 KiB — 482 ms — h2https://linuxfr.org/images/sections/19.png/images/sections/19.png https://linuxfr.org/images/sections/19.png — 200 — 2.6 KiB — 522 ms — h2https://linuxfr.org/images/logos/logo-linuxfr-cadre-dehors.png/images/logos/logo-linuxfr-cadre-de... https://linuxfr.org/images/logos/logo-linuxfr-cadre-dehors.png — 200 — 16.3 KiB — 426 ms — h2data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20widt…data:image/svg+xml;charset=utf-8,%3... data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20widt… — 200 — 0 B — 0 ms — datahttps://linuxfr.org/images/contrib/RonRonnement/coin-transparent.png/images/contrib/RonRonnement/coin-t... https://linuxfr.org/images/contrib/RonRonnement/coin-transparent.png — 200 — 396 B — 463 ms — h2https://linuxfr.org/images/icones/download.svg/images/icones/download.svg https://linuxfr.org/images/icones/download.svg — 200 — 2.8 KiB — 503 ms — h2data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20widt…data:image/svg+xml;charset=utf-8,%3... data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20widt… — 200 — 0 B — 0 ms — datadata:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20widt…data:image/svg+xml;charset=utf-8,%3... data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20widt… — 200 — 0 B — 0 ms — datahttps://linuxfr.org/fonts/Lato-Regular.woff2/fonts/Lato-Regular.woff2 https://linuxfr.org/fonts/Lato-Regular.woff2 — 200 — 178.9 KiB — 472 ms — h2https://linuxfr.org/fonts/Merriweather-Regular.woff2/fonts/Merriweather-Regular.woff2 https://linuxfr.org/fonts/Merriweather-Regular.woff2 — 200 — 102.6 KiB — 480 ms — h2https://linuxfr.org/favicon.png/favicon.png https://linuxfr.org/favicon.png — 200 — 2.0 KiB — 193 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
22% of JavaScript execution is third-party
First-party Third-party 228ms · 0KB · €2/mo
Unattributable
Other
Costly
Execution 228ms
Transfer 0 KB
Monthly Cost €2/mo

These scripts may cost more than they're worth

  • Unattributable adds 228ms and costs ~€2/month

Unattributable takes 228ms 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

Real-User Performance (CrUX)
Field metrics from the Chrome User Experience Report
INFO

Chrome User Experience (CrUX)

Real-user metrics from the Chrome UX Report (2026-03-24 — 2026-04-20)

LCP (p75)

1089 ms

97% good

INP (p75)

51 ms

99% good

CLS (p75)

0.010

96% good

FCP (p75)

874 ms

TTFB (p75)

589 ms

This origin passes Core Web Vitals assessment
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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