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https://www.sorbonne-universite.fr

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
84
GRADE
B
FIX
2
REVIEW
4
PASS
8
INFO
2

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

Mobile Desktop
53
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
80
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.
85
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.

4.05 s

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

7.56 s

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

494 ms

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

0.006

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

4.65 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.

7.56 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
8 PASS 4 REVIEW 2 FIX
F
JS Execution Cost
Action
3802ms total JS execution
FIX
3802ms total JS execution
Warning::
https://www.sorbonne-universite.fr/sites/default/f...: 1931ms CPU time
Warning::
https://www.sorbonne-universite.fr/: 1038ms CPU time
Warning::
https://admin-pipeline.upsun-fr-3.observability-pi...: 501ms CPU time
Warning::
Unattributable: 271ms CPU time
Info::
https://analytics.sorbonne-universite.fr/matomo/ma...: 61ms CPU time
Info::
Third-party scripts: 833ms (22% of total)

Main Thread Breakdown

Style & Layout 31% Script Evaluation 30% Other 23% Rendering 9% Script Parsing & Compilation 4%
ScriptTotalScriptingParse/CompileParty
https://www.sorbonne-universite.fr/sites/default/files/js/js_OwpWkPscNXGTcv-zoqQPTy9uW9Frnxx47WsrScrXTKo.js?scope=footer&delta=1&language=fr&theme=boots&include=eJx1jEEOwjAMBD9k4SdFbroFq04cJY5Ufk8FPdLTaOYwCyLQE47mA2va1E4d_ERFF6PFPQaPeBsIM2X3XXGiNFOpGfwvEo4wrTuvfTaxx6VkkM0QfJGKhBfnH2hAen4laZpkhn93CPBN_wC9Skmf1931ms783ms119ms1st
https://www.sorbonne-universite.fr/1038ms12ms2ms1st
https://admin-pipeline.upsun-fr-3.observability-pipeline.blackfire.io/js/probe.js501ms302ms11ms3rd
Unattributable271ms12ms0ms3rd
https://analytics.sorbonne-universite.fr/matomo/matomo.js61ms43ms9ms3rd
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: no-store, no-cache, must-revalidate, max-age=0
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present
Cache-Control

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

DirectiveValueMeaning
no-store—Never cache this response
no-cache—Cache but always revalidate first
must-revalidate—Must recheck with server after expiry
max-age0Cache for 0 seconds
B
Page Weight Budget
1.1 MB transferred, 47 requests
REVIEW
1.1 MB transferred, 47 requests
Info::
Page weighs 2.5 MB (1.1 MB transferred)
Info::
Fonts are 210 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 210 KB
Info::
47 HTTP requests
Info::
Estimated 0.24 g CO2 per page load
1.1 MB / 2.4 MB budget
1.1 MB transferred
47 requests
0.24 g CO2 per page load
JavaScript 487.0 KiB 42%
Images 368.0 KiB 32%
Fonts 210.5 KiB 18%
CSS 70.9 KiB 6%
HTML 28.2 KiB 2%
Other 505 B 0%
Other 267 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

C
Image Optimization
Action
12 images, 0 KB saveable
REVIEW
12 images, 0 KB saveable
Warning::
https://www.sorbonne-universite.fr/sites/default/f... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.sorbonne-universite.fr/themes/custom/b... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
12 images 368 KB
0 oversized -0 KB
11 legacy format
2 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

C
JS Bundles
Action
7 scripts, 265 KB unused
REVIEW
7 scripts, 265 KB unused
Warning::
https://www.sorbonne-universite.fr/sites/default/f...: 197 KB unused (66%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://analytics.sorbonne-universite.fr/matomo/ma...: 38 KB unused (59%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://admin-pipeline.upsun-fr-3.observability-pi...: 30 KB unused (32%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 265 KB
265 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.sorbonne-universite.fr/sites/default/files/js/js_OwpWkPscNXGTcv-zoqQPTy9uW9Frnxx47WsrScrXTKo.js?scope=footer&delta=1&language=fr&theme=boots&include=eJx1jEEOwjAMBD9k4SdFbroFq04cJY5Ufk8FPdLTaOYwCyLQE47mA2va1E4d_ERFF6PFPQaPeBsIM2X3XXGiNFOpGfwvEo4wrTuvfTaxx6VkkM0QfJGKhBfnH2hAen4laZpkhn93CPBN_wC9Skmf298 KB197 KB (66%)✓1st
https://analytics.sorbonne-universite.fr/matomo/matomo.js65 KB38 KB (59%)✓3rd
https://admin-pipeline.upsun-fr-3.observability-pipeline.blackfire.io/js/probe.js97 KB30 KB (32%)✓3rd
https://www.sorbonne-universite.fr/core/assets/vendor/jquery/jquery.min.js?v=4.0.0-rc.127 KB—✓1st
https://ingest.upsun-fr-3.observability-pipeline.blackfire.io/browser/v1/input/metrics?k=4c1331573e43e33f36e77b4c931d87ef46359e1e60c6d487d3e345351691b40f&u=4.1&s=H4sIAAAAAAACA41PzW7DIBh7F85pm0B-KNf1ASZNu0WKCHy0mQhEQBpNVd59kLbrjjthG9uYGxKIoZObJ67bVsw-2LETdhytads3a4KzWoNr2xMoPuvwkhi72BHe-RlQhuZYcglh8uxwWJZl763rrTGwm81wBeeHAHvlDtHpESsypKMfzO7zIypfYYisOFa9UIAxkX2BK1LRnDZNXdclpnUhihTdjLQWioqjqlROCCWKVLIXpQRolGykktF4_XdjJxG7oaUbFsTKAmcJXhCjmKRL_gfGxfkGwhM8I74TsQWXCb0CQ_yo4tpDIpY_QjamkeZGesEn2E1uGLn73pZMvyX34jVD4j5vO_JEIcXLM0rYhfBQvXw8ta4_OrCKUc8BAAA&t=H4sIAAAAAAACAy3MQQqAIBAF0Lv8tYUzOWpeJqgmaBNRUkR49wraP96NjIRVt6nSJW8XDHYkCkGkdc5KzcwGI9KN3M0vpVb6YVLmZuyJpZFoYwjee8fR00D4tX7vMeuJUsoDGcEhnWYAAAA.H4sIAAAAAAACA0WNQQoDIQxF75K1DqNjGHTZRU_gBSyKCFZLxzqUwbs3pS3dBJKX9_8BDQzs4cJ7ai5vwGADI9YVUSs14yQXycCDOT6juGsgwdrziV67yw9ahZqQwd21VCLBWKsn6ENu7gcT2dCR_5OllFwIFBo14jJrQUpxPUWKqcU-b--e7yHAGOMFI23ZGasAAAA0 KB—✓3rd
https://ingest.upsun-fr-3.observability-pipeline.blackfire.io/browser/v1/input/metrics?k=4c1331573e43e33f36e77b4c931d87ef46359e1e60c6d487d3e345351691b40f&u=4.1&s=H4sIAAAAAAACA41PzW7DIBh7F85pm0B-KNf1ASZNu0WKCHy0mQhEQBpNVd59kLbrjjthG9uYGxKIoZObJ67bVsw-2LETdhytads3a4KzWoNr2xMoPuvwkhi72BHe-RlQhuZYcglh8uxwWJZl763rrTGwm81wBeeHAHvlDtHpESsypKMfzO7zIypfYYisOFa9UIAxkX2BK1LRnDZNXdclpnUhihTdjLQWioqjqlROCCWKVLIXpQRolGykktF4_XdjJxG7oaUbFsTKAmcJXhCjmKRL_gfGxfkGwhM8I74TsQWXCb0CQ_yo4tpDIpY_QjamkeZGesEn2E1uGLn73pZMvyX34jVD4j5vO_JEIcXLM0rYhfBQvXw8ta4_OrCKUc8BAAA&t=H4sIAAAAAAACAxWOSw7DIBBD7zLrFIgYSsNlqgkflQ1EQMIiyt0LK9tPluUbGhhohVKNLeYEC1Qwq9ZKbYhCMZRqAQfmhusbR1XQ9iZnd0LCj5UyCPRaWr9ajUTBjoG56GLxto0QzpEmPIbyaSb4tXZUw3nvndVc9pySf50pXr6MH56FwuF5_lgX_uWdAAAA0 KB—✓3rd
https://ingest.upsun-fr-3.observability-pipeline.blackfire.io/browser/v1/input/metrics?k=4c1331573e43e33f36e77b4c931d87ef46359e1e60c6d487d3e345351691b40f&u=4.1&s=H4sIAAAAAAACA41PzW7DIBh7F85pm0B-KNf1ASZNu0WKCHy0mQhEQBpNVd59kLbrjjthG9uYGxKIoZObJ67bVsw-2LETdhytads3a4KzWoNr2xMoPuvwkhi72BHe-RlQhuZYcglh8uxwWJZl763rrTGwm81wBeeHAHvlDtHpESsypKMfzO7zIypfYYisOFa9UIAxkX2BK1LRnDZNXdclpnUhihTdjLQWioqjqlROCCWKVLIXpQRolGykktF4_XdjJxG7oaUbFsTKAmcJXhCjmKRL_gfGxfkGwhM8I74TsQWXCb0CQ_yo4tpDIpY_QjamkeZGesEn2E1uGLn73pZMvyX34jVD4j5vO_JEIcXLM0rYhfBQvXw8ta4_OrCKUc8BAAA&t=H4sIAAAAAAACA0WNQQ4CIQxF79I1mIEBEbYmrl14gRoIIUEwDmLMhLtbo8ZNm_b1_a7QwMEjnHlPDfMCDBZwwhitrVKT3uysZeDBrZ9S8BJIOOyPdNkx32kSs1IMbthSicRirZ6gD7nhDyaSoWv-D5ZScmtnYY2eJLUtKQV7ihRTy-l5fb_5LgKMMV4XU6o9qgAAAA0 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

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

Green Hosting

No green hosting detected

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 (355.7 KiB of 1.1 MiB)
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
12 fonts (210 KB)
PASS
12 fonts (210 KB)
Info::
12 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

12

210 KB total

Render-blocking

0

of 12

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 FCP 4.1 s LCP 7.6 shttps://fonts.gstatic.com/s/barlow/v13/7cHqv4kjgoGqM7E3t-4s51ostz0rdg.woff27cHqv4kjgoGqM7E3t-4s51o... https://fonts.gstatic.com/s/barlow/v13/7cHqv4kjgoGqM7E3t-4s51ostz0rdg.woff2 — 15.4 KiB — 0 ms — font-display: swaphttps://www.sorbonne-universite.fr/themes/custom/boots/assets/fonts/icomoon/icomoon.woff2?1wk5k2=icomoon.woff2 https://www.sorbonne-universite.fr/themes/custom/boots/assets/fonts/icomoon/icomoon.woff2?1wk5k2= — 21.1 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/barlow/v13/7cHqv4kjgoGqM7E3_-gs51ostz0rdg.woff27cHqv4kjgoGqM7E3_-gs51o... https://fonts.gstatic.com/s/barlow/v13/7cHqv4kjgoGqM7E3_-gs51ostz0rdg.woff2 — 15.3 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/barlow/v13/7cHpv4kjgoGqM7E_DMs5ynghnQ.woff27cHpv4kjgoGqM7E_DMs5yng... https://fonts.gstatic.com/s/barlow/v13/7cHpv4kjgoGqM7E_DMs5ynghnQ.woff2 — 15.3 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/barlow/v13/7cHqv4kjgoGqM7E30-8s51ostz0rdg.woff27cHqv4kjgoGqM7E30-8s51o... https://fonts.gstatic.com/s/barlow/v13/7cHqv4kjgoGqM7E30-8s51ostz0rdg.woff2 — 15.5 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/barlow/v13/7cHqv4kjgoGqM7E3p-ks51ostz0rdg.woff27cHqv4kjgoGqM7E3p-ks51o... https://fonts.gstatic.com/s/barlow/v13/7cHqv4kjgoGqM7E3p-ks51ostz0rdg.woff2 — 15.2 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/crimsontext/v19/wlpogwHKFkZgtmSR3NB0oRJfajhRK_Z_3rhH.woff2wlpogwHKFkZgtmSR3NB0oRJ... https://fonts.gstatic.com/s/crimsontext/v19/wlpogwHKFkZgtmSR3NB0oRJfajhRK_Z_3rhH.woff2 — 17.0 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/ubuntu/v21/4iCv6KVjbNBYlgoCxCvjsGyNPYZvgw.woff24iCv6KVjbNBYlgoCxCvjsGy... https://fonts.gstatic.com/s/ubuntu/v21/4iCv6KVjbNBYlgoCxCvjsGyNPYZvgw.woff2 — 14.6 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/ubuntu/v21/4iCs6KVjbNBYlgoKfw72nU6AFw.woff24iCs6KVjbNBYlgoKfw72nU6... https://fonts.gstatic.com/s/ubuntu/v21/4iCs6KVjbNBYlgoKfw72nU6AFw.woff2 — 13.8 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/lora/v37/0QIvMX1D_JOuMwr7I_FMl_E.woff20QIvMX1D_JOuMwr7I_FMl_E... https://fonts.gstatic.com/s/lora/v37/0QIvMX1D_JOuMwr7I_FMl_E.woff2 — 36.9 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/ubuntu/v21/4iCv6KVjbNBYlgoCjC3jsGyNPYZvgw.woff24iCv6KVjbNBYlgoCjC3jsGy... https://fonts.gstatic.com/s/ubuntu/v21/4iCv6KVjbNBYlgoCjC3jsGyNPYZvgw.woff2 — 14.0 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/crimsontext/v19/wlp2gwHKFkZgtmSR3NB0oRJfbwhTIfFd3A.woff2wlp2gwHKFkZgtmSR3NB0oRJ... https://fonts.gstatic.com/s/crimsontext/v19/wlp2gwHKFkZgtmSR3NB0oRJfbwhTIfFd3A.woff2 — 16.4 KiB — 0 ms — font-display: swap
7cHqv4kjgoGqM7E3t-4s51o... woff2 swap
Size 15 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
icomoon.woff2 woff2 swap
Size 21 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
7cHqv4kjgoGqM7E3_-gs51o... woff2 swap
Size 15 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
7cHpv4kjgoGqM7E_DMs5yng... woff2 swap
Size 15 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
7cHqv4kjgoGqM7E30-8s51o... woff2 swap
Size 15 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
7cHqv4kjgoGqM7E3p-ks51o... woff2 swap
Size 15 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
wlpogwHKFkZgtmSR3NB0oRJ... woff2 swap
Size 17 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
4iCv6KVjbNBYlgoCxCvjsGy... woff2 swap
Size 15 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
4iCs6KVjbNBYlgoKfw72nU6... woff2 swap
Size 14 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
0QIvMX1D_JOuMwr7I_FMl_E... woff2 swap
Size 37 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
4iCv6KVjbNBYlgoCjC3jsGy... woff2 swap
Size 14 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
wlp2gwHKFkZgtmSR3NB0oRJ... woff2 swap
Size 16 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
47 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
22% of JavaScript execution is third-party
First-party Third-party 833ms · 161KB · €9/mo
admin-pipeline.upsun-fr-3.observability-pipeline.blackfire.io
Other
Costly
Execution 501ms
Transfer 97 KB
Unused 32%
Monthly Cost €5/mo
Unattributable
Other
Costly
Execution 271ms
Transfer 0 KB
Monthly Cost €3/mo
analytics.sorbonne-universite.fr
Other
Optional
Execution 61ms
Transfer 65 KB
Unused 59%
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • admin-pipeline.upsun-fr-3.observability-pipeline.blackfire.io adds 501ms and costs ~€5/month
  • Unattributable adds 271ms and costs ~€3/month

admin-pipeline.upsun-fr-3.observability-pipeline.blackfire.io takes 501ms 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

Unattributable takes 271ms 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

59% of analytics.sorbonne-universite.fr'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

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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