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https://www.leboncoin.fr

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
73
GRADE
C
FIX
4
REVIEW
3
PASS
7
INFO
2

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

20
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
84
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.
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.

3.50 s

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

8.93 s

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

11.38 s

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

0.201

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

11.43 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.

28.75 s

Page Load Progression

855 ms
1.7 s
2.6 s
3.4 s
4.3 s
5.1 s
6.0 s
6.8 s
Checks
16
7 PASS 3 REVIEW 4 FIX
F
Page Weight Budget
Action
4.0 MB transferred, 256 requests
FIX
4.0 MB transferred, 256 requests
Critical::
Page weighs 15.8 MB (4.0 MB transferred)
Warning::
JavaScript is 2.1 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 2.1 MB
Warning::
256 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 0.83 g CO2 per page load
4.0 MB / 2.4 MB budget
4.0 MB transferred
256 requests
0.83 g CO2 per page load
JavaScript 2.1 MiB 53%
Images 641.6 KiB 16%
HTML 527.3 KiB 13%
Other 411.1 KiB 10%
Other 201.3 KiB 5%
CSS 71.7 KiB 2%
Fonts 46.7 KiB 1%
Other 4.7 KiB 0%
Other 2.2 KiB 0%
Other 1.2 KiB 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

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

Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

F
JS Execution Cost
Action
25524ms total JS execution
FIX
25524ms total JS execution
Warning::
https://www.leboncoin.fr/_next/static/chunks/frame...: 6075ms CPU time
Warning::
https://www.leboncoin.fr/: 2799ms CPU time
Warning::
Unattributable: 2741ms CPU time
Warning::
https://cdn.hubvisor.io/wrapper/01CE9HZCZVPW9QB522...: 2385ms CPU time
Warning::
https://www.leboncoin.fr/_next/static/chunks/pages...: 1817ms CPU time
Info::
Third-party scripts: 9899ms (39% of total)

Main Thread Breakdown

Script Evaluation 61% Style & Layout 14% Other 10% Script Parsing & Compilation 9%
ScriptTotalScriptingParse/CompileParty
https://www.leboncoin.fr/_next/static/chunks/framework-2abbcfecf697e9a2.js6075ms4135ms28ms1st
https://www.leboncoin.fr/2799ms176ms16ms1st
Unattributable2741ms1017ms0ms3rd
https://cdn.hubvisor.io/wrapper/01CE9HZCZVPW9QB522QNNS8MZQ/hubvisor.js2385ms1815ms567ms3rd
https://www.leboncoin.fr/_next/static/chunks/pages/_app-4542fcc57fd47f46.js1817ms1374ms313ms1st
https://www.leboncoin.fr/_next/static/chunks/70025.a7433be5f391f1c1.js1424ms1386ms4ms1st
https://sdk.privacy-center.org/sdk/c8e2e67c354c0d6dec2981e079061b37f6a1f337/modern/sdk.c8e2e67c354c0d6dec2981e079061b37f6a1f337.js1375ms1034ms217ms3rd
https://server.sgtm.leboncoin.fr/gtm.js?id=GTM-PXTWK33X783ms596ms90ms3rd
https://dd.leboncoin.fr/tags.js632ms520ms26ms3rd
https://www.leboncoin.fr/_next/static/chunks/7730-514c76803cf21dba.js571ms516ms32ms1st

Showing top 10 of 30 scripts

F
JS Bundles
Action
138 scripts, 2.3 MB unused
FIX
138 scripts, 2.3 MB unused
Warning::
https://www.leboncoin.fr/_next/static/chunks/pages...: 208 KB unused (43%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.leboncoin.fr/_next/static/chunks/44700...: 166 KB unused (98%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.leboncoin.fr/_next/static/chunks/44700...: 166 KB unused (98%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.leboncoin.fr/_next/static/chunks/1607-...: 150 KB unused (97%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.leboncoin.fr/_next/static/chunks/1607-...: 150 KB unused (97%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 2.3 MB
2388 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.leboncoin.fr/_next/static/chunks/pages/_app-4542fcc57fd47f46.js479 KB208 KB (43%)✓1st
https://www.leboncoin.fr/_next/static/chunks/44700-c58766aeb527c730.js58 KB166 KB (98%)✓1st
https://www.leboncoin.fr/_next/static/chunks/44700-c58766aeb527c730.js0 KB166 KB (98%)✓1st
https://www.leboncoin.fr/_next/static/chunks/1607-1321761431f1d26c.js57 KB150 KB (97%)✓1st
https://www.leboncoin.fr/_next/static/chunks/1607-1321761431f1d26c.js0 KB150 KB (97%)✓1st
https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604020101/pubads_impl.js183 KB139 KB (76%)✓3rd
https://www.leboncoin.fr/_next/static/chunks/17645-ef23547b8a8fdebf.js0 KB137 KB (84%)✓1st
https://www.leboncoin.fr/_next/static/chunks/17645-ef23547b8a8fdebf.js50 KB137 KB (84%)✓1st
https://server.sgtm.leboncoin.fr/gtag/js?id=G-Z707449XJ2&cx=c&gtm=4e6461h2&sign=f9b7a61e095da83b1a7c2eaa6c45a18a38eea262bf23b0cc5791a12f859dc1cd_20260407161 KB73 KB (45%)✓3rd
https://server.sgtm.leboncoin.fr/gtm.js?id=GTM-PXTWK33X168 KB71 KB (42%)✓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

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
HTTP Caching
Action
no-store (uncacheable)
FIX
no-store (uncacheable)
Info::
Cache-Control: no-store prevents all caching
Intentional for dynamic content, but increases server load for every page view.
Got: max-age=0, private, no-cache, no-store, must-revalidate
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

max-age=0, private, no-cache, no-store, must-revalidate

DirectiveValueMeaning
max-age0Cache for 0 seconds
private—Only browser cache, not CDN/proxy
no-cache—Cache but always revalidate first
no-store—Never cache this response
must-revalidate—Must recheck with server after expiry
B
Third-Party Impact
60% third-party, 0 ms blocking
REVIEW
60% third-party, 0 ms blocking
Warning::
Third-party code accounts for 60% of page weight (2.4 MiB of 4.0 MiB)
Info::
Third-party blocking time is low (0 ms)
40%
60%
First-party Third-party
B
Image Optimization
42 images, 0 KB saveable
REVIEW
42 images, 0 KB saveable
Info::
All images are well-optimized
42 images 642 KB
0 oversized -0 KB
31 legacy format
0 missing dimensions CLS risk
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+
Font Loading
3 fonts (47 KB)
PASS
3 fonts (47 KB)
Info::
3 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

3

47 KB total

Render-blocking

0

of 3

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 6.0 s 7.0 s 8.0 s 9.0 s FCP 3.5 s LCP 8.9 shttps://www.leboncoin.fr/_next/static/media/68180864d7f93f02-s.p.woff268180864d7f93f02-s.p.woff2 https://www.leboncoin.fr/_next/static/media/68180864d7f93f02-s.p.woff2 — 30.9 KiB — 0 ms — font-display: swaphttps://static.captcha-delivery.com/common/fonts/roboto/roboto.woff2roboto.woff2 https://static.captcha-delivery.com/common/fonts/roboto/roboto.woff2 — 15.8 KiB — 0 ms — font-display: swaphttps://static.captcha-delivery.com/common/fonts/roboto/roboto.woff2roboto.woff2 https://static.captcha-delivery.com/common/fonts/roboto/roboto.woff2 — 0 B — 0 ms — font-display: swap
68180864d7f93f02-s.p.woff2 woff2 swap
Size 31 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
roboto.woff2 woff2 swap
Size 16 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
roboto.woff2 woff2 swap
Size 0 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
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
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
256 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
39% of JavaScript execution is third-party
First-party Third-party 9899ms · 973KB · €107/mo
Unattributable
Other
Costly
Execution 2741ms
Transfer 0 KB
Monthly Cost €30/mo
cdn.hubvisor.io
Other
Costly
Execution 2385ms
Transfer 365 KB
Unused 18%
Monthly Cost €26/mo
sdk.privacy-center.org
Other
Costly
Execution 1375ms
Transfer 0 KB
Unused 40%
Monthly Cost €15/mo
server.sgtm.leboncoin.fr
Other
Costly
Execution 783ms
Transfer 168 KB
Unused 42%
Monthly Cost €8/mo
dd.leboncoin.fr
Other
Costly
Execution 632ms
Transfer 43 KB
Monthly Cost €7/mo
sdk.privacy-center.org
Other
Costly
Execution 456ms
Transfer 0 KB
Unused 41%
Monthly Cost €5/mo
server.sgtm.leboncoin.fr
Other
Costly
Execution 379ms
Transfer 161 KB
Unused 45%
Monthly Cost €4/mo
sdk.privacy-center.org
Other
Costly
Execution 368ms
Transfer 0 KB
Monthly Cost €4/mo
securepubads.g.doubleclick.net
Other
Costly
Execution 328ms
Transfer 183 KB
Unused 76%
Monthly Cost €4/mo
sdk.privacy-center.org
Other
Costly
Execution 204ms
Transfer 0 KB
Monthly Cost €2/mo
securepubads.g.doubleclick.net
Other
Optional
Execution 146ms
Transfer 34 KB
Monthly Cost €2/mo
cdn-eu.realytics.net
Other
Optional
Execution 104ms
Transfer 19 KB
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • Unattributable adds 2741ms and costs ~€30/month
  • cdn.hubvisor.io adds 2385ms and costs ~€26/month
  • sdk.privacy-center.org adds 1375ms and costs ~€15/month
  • server.sgtm.leboncoin.fr adds 783ms and costs ~€8/month
  • dd.leboncoin.fr adds 632ms and costs ~€7/month
  • sdk.privacy-center.org adds 456ms and costs ~€5/month
  • server.sgtm.leboncoin.fr adds 379ms and costs ~€4/month
  • sdk.privacy-center.org adds 368ms and costs ~€4/month
  • securepubads.g.doubleclick.net adds 328ms and costs ~€4/month
  • sdk.privacy-center.org adds 204ms and costs ~€2/month

Unattributable takes 2741ms 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

cdn.hubvisor.io takes 2385ms 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

sdk.privacy-center.org takes 1375ms 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

server.sgtm.leboncoin.fr takes 783ms 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

dd.leboncoin.fr takes 632ms 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

sdk.privacy-center.org takes 456ms 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

server.sgtm.leboncoin.fr takes 379ms 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

sdk.privacy-center.org takes 368ms 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 328ms 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

76% 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

sdk.privacy-center.org takes 204ms 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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