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https://www.lemonde.fr

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
87
GRADE
B
FIX
1
REVIEW
4
PASS
9
INFO
2

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

Mobile Desktop
55
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
88
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.
92
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.

5.32 s

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

10.07 s

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

276 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.

6.10 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.

10.12 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
16
9 PASS 4 REVIEW 1 FIX
D
JS Execution Cost
Action
2786ms total JS execution
FIX
2786ms total JS execution
Warning::
https://www.lemonde.fr/: 833ms CPU time
Warning::
https://www.lemonde.fr/bucket/resources/front/js/c...: 415ms CPU time
Warning::
Unattributable: 403ms CPU time
Warning::
https://securepubads.g.doubleclick.net/pagead/mana...: 278ms CPU time
Warning::
https://cdn.sitestream.co/libs/storylines/5.0.12/s...: 251ms CPU time
Info::
Third-party scripts: 1137ms (41% of total)

Main Thread Breakdown

Script Evaluation 36% Style & Layout 35% Other 16% Script Parsing & Compilation 8% Parse HTML & CSS 5%
ScriptTotalScriptingParse/CompileParty
https://www.lemonde.fr/833ms104ms7ms1st
https://www.lemonde.fr/bucket/resources/front/js/common.4cffe894c125a193.js415ms153ms19ms1st
Unattributable403ms31ms0ms3rd
https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604020101/pubads_impl.js278ms166ms81ms3rd
https://cdn.sitestream.co/libs/storylines/5.0.12/storylines.js251ms68ms26ms3rd
https://www.lemonde.fr/bucket/resources/front/js/home.11d1729d46f60f0e.js177ms134ms14ms1st
https://www.lemonde.fr/bucket/resources/front/96cb949ce39c9212.fb257ea3de19e0ff3ce52a6d43ff448cdad3ffd8.js161ms131ms9ms1st
https://securepubads.g.doubleclick.net/tag/js/gpt.js111ms94ms15ms3rd
https://cmp.lemonde.fr/js/lemonde.min.js94ms63ms24ms3rd
https://www.lemonde.fr/bucket/resources/front/03ea4fa719e85114.fb257ea3de19e0ff3ce52a6d43ff448cdad3ffd8.fb257ea3de19e0f.js63ms52ms10ms1st
B
Page Weight Budget
1.2 MB transferred, 78 requests
REVIEW
1.2 MB transferred, 78 requests
Info::
Page weighs 3.5 MB (1.2 MB transferred)
Info::
Fonts are 297 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 297 KB
Info::
CSS is 236 KB — consider purging unused styles
Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.
Got: 236 KB
Info::
78 HTTP requests
Info::
Estimated 0.26 g CO2 per page load
1.2 MB / 2.4 MB budget
1.2 MB transferred
78 requests
0.26 g CO2 per page load
JavaScript 495.1 KiB 39%
Fonts 296.9 KiB 24%
CSS 236.2 KiB 19%
Images 107.4 KiB 9%
HTML 70.7 KiB 6%
Other 31.2 KiB 2%
Other 12.8 KiB 1%
Other 2.9 KiB 0%
Other 1.1 KiB 0%
Other 157 B 0%
Other 0 B 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

Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.

Why this matters

CSS bundle is large — purge unused styles (PurgeCSS, Tailwind JIT) to reduce CSS payload.

Source: web.dev

C
JS Bundles
Action
16 scripts, 213 KB unused
REVIEW
16 scripts, 213 KB unused
Warning::
https://securepubads.g.doubleclick.net/pagead/mana...: 140 KB unused (77%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.sitestream.co/libs/storylines/5.0.12/s...: 28 KB unused (49%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.lemonde.fr/bucket/resources/front/js/c...: 23 KB unused (59%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.lemonde.fr/bucket/resources/front/js/h...: 22 KB unused (67%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 213 KB
213 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604020101/pubads_impl.js183 KB140 KB (77%)✓3rd
https://cdn.sitestream.co/libs/storylines/5.0.12/storylines.js58 KB28 KB (49%)✓3rd
https://www.lemonde.fr/bucket/resources/front/js/common.4cffe894c125a193.js40 KB23 KB (59%)✓1st
https://www.lemonde.fr/bucket/resources/front/js/home.11d1729d46f60f0e.js33 KB22 KB (67%)✓1st
https://www.lemonde.fr/bucket/resources/front/ca618854ca95a48e.fb257ea3de19e0ff3ce52a6d43ff448cdad3ffd8.43260.js25 KB—✓1st
https://applets.ebxcdn.com/ebx.js1 KB—✓3rd
https://www.lemonde.fr/bucket/resources/front/96cb949ce39c9212.fb257ea3de19e0ff3ce52a6d43ff448cdad3ffd8.js20 KB—✓1st
https://www.lemonde.fr/bucket/resources/front/js/forecast.ab75835444be58f0.js11 KB—✓1st
https://cmp.lemonde.fr/js/lemonde.min.js48 KB—✓3rd
https://www.lemonde.fr/bucket/resources/front/03ea4fa719e85114.fb257ea3de19e0ff3ce52a6d43ff448cdad3ffd8.fb257ea3de19e0f.js25 KB—✓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

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

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

Green Hosting

No green hosting detected

B
HTTP Caching
private, must-revalidate, max-age=0
REVIEW
private, must-revalidate, max-age=0
Info::
Cache-Control header is set
Got: private, must-revalidate, max-age=0
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

private, must-revalidate, max-age=0

DirectiveValueMeaning
private—Only browser cache, not CDN/proxy
must-revalidate—Must recheck with server after expiry
max-age0Cache for 0 seconds
A
Third-Party Impact
39% third-party, 0 ms blocking
PASS
39% third-party, 0 ms blocking
Info::
Third-party code accounts for 39% of page weight (487.6 KiB of 1.2 MiB)
Info::
Third-party blocking time is low (0 ms)
61%
39%
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
Image Optimization
16 images, 0 KB saveable
PASS
16 images, 0 KB saveable
Info::
All images are well-optimized
16 images 107 KB
0 oversized -0 KB
2 legacy format
0 missing dimensions CLS risk
A+
Font Loading
8 fonts (297 KB)
PASS
8 fonts (297 KB)
Info::
8 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

8

297 KB total

Render-blocking

0

of 8

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s FCP 5.3 s LCP 10.1 shttps://www.lemonde.fr/bucket/resources/front/front/fonts/marr-sans/MarrSans-Medium-Web.ac7bf37b26f16e97.woff2MarrSans-Medium-Web.ac7... https://www.lemonde.fr/bucket/resources/front/front/fonts/marr-sans/MarrSans-Medium-Web.ac7bf37b26f16e97.woff2 — 32.4 KiB — 0 ms — font-display: swaphttps://www.lemonde.fr/bucket/resources/front/front/fonts/marr-sans-cond/MarrSansCondensed-Medium-Web.133dea79c01db68e.woff2MarrSansCondensed-Mediu... https://www.lemonde.fr/bucket/resources/front/front/fonts/marr-sans-cond/MarrSansCondensed-Medium-Web.133dea79c01db68e.woff2 — 39.3 KiB — 0 ms — font-display: swaphttps://www.lemonde.fr/bucket/resources/front/front/fonts/variables/the-antiqua-b/TheAntiquaB-LeMonde.b353d5d190089f96.woff2TheAntiquaB-LeMonde.b35... https://www.lemonde.fr/bucket/resources/front/front/fonts/variables/the-antiqua-b/TheAntiquaB-LeMonde.b353d5d190089f96.woff2 — 40.7 KiB — 0 ms — font-display: swaphttps://www.lemonde.fr/bucket/resources/front/front/fonts/marr-sans/MarrSans-Regular-Web.2f89fff3877253bf.woff2MarrSans-Regular-Web.2f... https://www.lemonde.fr/bucket/resources/front/front/fonts/marr-sans/MarrSans-Regular-Web.2f89fff3877253bf.woff2 — 31.2 KiB — 0 ms — font-display: swaphttps://www.lemonde.fr/bucket/resources/front/front/fonts/marr-sans/MarrSans-Semibold-Web.f7d5c05af8370693.woff2MarrSans-Semibold-Web.f... https://www.lemonde.fr/bucket/resources/front/front/fonts/marr-sans/MarrSans-Semibold-Web.f7d5c05af8370693.woff2 — 32.1 KiB — 0 ms — font-display: swaphttps://www.lemonde.fr/bucket/resources/front/front/fonts/marr-sans-cond/MarrSansCondensed-Semibold-Web.22ed62e40765ed70.woff2MarrSansCondensed-Semib... https://www.lemonde.fr/bucket/resources/front/front/fonts/marr-sans-cond/MarrSansCondensed-Semibold-Web.22ed62e40765ed70.woff2 — 39.6 KiB — 0 ms — font-display: swaphttps://www.lemonde.fr/bucket/resources/front/front/fonts/marr-sans-cond/MarrSansCondensed-Bold-Web.07e8c5aa145a2514.woff2MarrSansCondensed-Bold-... https://www.lemonde.fr/bucket/resources/front/front/fonts/marr-sans-cond/MarrSansCondensed-Bold-Web.07e8c5aa145a2514.woff2 — 39.5 KiB — 0 ms — font-display: swaphttps://www.lemonde.fr/bucket/resources/front/front/fonts/variables/the-antiqua-b/TheAntiquaB-LeMonde-Italic.a9ec17f6e3f905ea.woff2TheAntiquaB-LeMonde-Ita... https://www.lemonde.fr/bucket/resources/front/front/fonts/variables/the-antiqua-b/TheAntiquaB-LeMonde-Italic.a9ec17f6e3f905ea.woff2 — 41.9 KiB — 0 ms — font-display: swap
MarrSans-Medium-Web.ac7... woff2 swap
Size 32 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
MarrSansCondensed-Mediu... woff2 swap
Size 39 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
TheAntiquaB-LeMonde.b35... woff2 swap
Size 41 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
MarrSans-Regular-Web.2f... woff2 swap
Size 31 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
MarrSans-Semibold-Web.f... woff2 swap
Size 32 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
MarrSansCondensed-Semib... woff2 swap
Size 40 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
MarrSansCondensed-Bold-... woff2 swap
Size 40 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
TheAntiquaB-LeMonde-Ita... woff2 swap
Size 42 KB
Load time 0 ms
Start 0 ms
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
4 hints, 0 missing preconnects
PASS
4 hints, 0 missing preconnects
Info::
Page uses 4 resource hint(s)

Current Resource Hints

preconnect
1
preload
3
dns-prefetch
—
prefetch
—

4 resource hints configured

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
78 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
41% of JavaScript execution is third-party
First-party Third-party 1137ms · 323KB · €5/mo
Unattributable
Other
Costly
Execution 403ms
Transfer 0 KB
Monthly Cost €2/mo
securepubads.g.doubleclick.net
Other
Costly
Execution 278ms
Transfer 183 KB
Unused 77%
Monthly Cost €1/mo
cdn.sitestream.co
Other
Costly
Execution 251ms
Transfer 58 KB
Unused 49%
Monthly Cost €1/mo
securepubads.g.doubleclick.net
Other
Optional
Execution 111ms
Transfer 34 KB
Monthly Cost €0/mo
cmp.lemonde.fr
Other
Optional
Execution 94ms
Transfer 48 KB
Monthly Cost €0/mo

These scripts may cost more than they're worth

  • Unattributable adds 403ms and costs ~€2/month
  • securepubads.g.doubleclick.net adds 278ms and costs ~€1/month
  • cdn.sitestream.co adds 251ms and costs ~€1/month

41% of JavaScript execution time comes from third-party scripts.

Why this matters

Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.

Learn more ▾

Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.

Source: web.dev / HTTP Archive Web Almanac

Unattributable takes 403ms 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

securepubads.g.doubleclick.net takes 278ms 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

77% of securepubads.g.doubleclick.net's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

cdn.sitestream.co takes 251ms 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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