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https://www.sorbonne-universite.fr

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
84
GRADE
B
FIX
1
REVIEW
5
PASS
6
INFO
2

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

Mobile Desktop
73
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
76
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.

909 ms

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

1.66 s

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

26 ms

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

0.418

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

1.18 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.

1.66 s

Page Load Progression

397 ms
794 ms
1.2 s
1.6 s
2.0 s
2.4 s
2.8 s
3.2 s
Checks
14
6 PASS 5 REVIEW 1 FIX
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, 46 requests
REVIEW
1.1 MB transferred, 46 requests
Info::
Page weighs 2.4 MB (1.1 MB transferred)
Info::
Fonts are 211 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 211 KB
Info::
46 HTTP requests
Info::
Estimated 0.23 g CO2 per page load
1.1 MB / 2.4 MB budget
1.1 MB transferred
46 requests
0.23 g CO2 per page load
JavaScript 486.7 KiB 44%
Images 306.6 KiB 28%
Fonts 210.5 KiB 19%
CSS 71.0 KiB 6%
HTML 28.2 KiB 3%
Other 491 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
13 images, 0 KB saveable
REVIEW
13 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.
13 images 307 KB
0 oversized -0 KB
12 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

B
JS Execution Cost
896ms total JS execution
REVIEW
896ms total JS execution
Warning::
https://www.sorbonne-universite.fr/sites/default/f...: 485ms CPU time
Info::
https://www.sorbonne-universite.fr/: 229ms CPU time
Info::
https://admin-pipeline.upsun-fr-3.observability-pi...: 109ms CPU time
Info::
Unattributable: 73ms CPU time
Info::
Third-party scripts: 182ms (20% of total)

Main Thread Breakdown

Other 28% Script Evaluation 28% Style & Layout 27% Rendering 10% 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_wC9Skmf485ms170ms36ms1st
https://www.sorbonne-universite.fr/229ms3ms0ms1st
https://admin-pipeline.upsun-fr-3.observability-pipeline.blackfire.io/js/probe.js109ms67ms2ms3rd
Unattributable73ms3ms0ms3rd
C
JS Bundles
Action
5 scripts, 267 KB unused
REVIEW
5 scripts, 267 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...: 32 KB unused (33%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 267 KB
267 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 KB32 KB (33%)✓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=H4sIAAAAAAACA42PzW7DIBCE34WzE__gv3BtHqBS1ZslC8OSuMJgAY5VRX73LnHaXHvi22VmGO5EEEbObpm57jqx-GCnXthpsqbr3qwJzmoNruvOoPiiw2vF2NVO8M4vQBKyYMg1hNmzNF3X9eitG6wxcFjMeAPnxwBH5VJUesLyhGjUgzl8fuDmK4w4NfVQCNXQvOSiaaq6BiigQh4EhSLPo_UhbGuhWnFSlcoobamilRxEKQEaJRupJApv_07sJWF3svbjirVolSWRr4SdyizecsQ62xEr7xB-AT3tfikwpigjvQwj_lRx7SEOlj9NFt1EcyO94DMcZjdO3H0_qsx_IXvwlhCx93scWRwh2ssLiexCeG69fD61bT8BTVHg0AEAAA&t=H4sIAAAAAAACAy3MOwqAMBBF0b28Ogoz5mc2IyaOYCOiQRHJ3o1gd4vDfZARsMk-N7Lm_YbCgUDOGdNrzdyS9woTwoM8LJU6GznNriM9pqqsFWExtWPqhInwa_m-5yIXSikvk6281GYAAAA.H4sIAAAAAAACA0WN3QoCIRBG32Wu3UjX_9uFrrvoBQxFBNNozYjFd2-ihW4GZs6c79uggYVXuE49NZdXILCCpUoJYThn7ECNJODBbr9R3C2gcFrO-NldfuLG9ZHAw7VUIqJYq0fmQ25uZwlV6GL6x1KtJylnyWZthBJGoVFcTxFTarm879-S_RBgjPEByEXT96gAAAA.H4sIAAAAAAACA0WNQQrDIBBF7zJrDTF1Gs2yi57AC1gUEayWxlhK8O6d0kA3AzNv3v87VFjg5W-8xWrTCgxWWMQ8I2opp2kQ-szAwbL_RrZ3T4Ix1wu9Nps2WvWADJ62xhyIhVIcMedTtQeL5EJD_s8VSvGTxGnUUqEeUZGRbYuBUko278e35Th46L1_ACxDzRupAAAA.H4sIAAAAAAACAxVOyw6EIBD7lzm7IsKEHX7GqIxZLmAA5WD894VTH2mbPlDAQklryL74GGCADFYag0haz_Oo5AAO7AP34ltyI0Os2CjckSb5NW6niSQR6hWR19bvg84n3ksTx9VUN8-GopNu_Eo5sxWi1jrmmLYYAn-u4G9O7QaPRxLwvn_LIlrWnAAAAA0 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
32% third-party, 0 ms blocking
PASS
32% third-party, 0 ms blocking
Info::
Third-party code accounts for 32% of page weight (355.5 KiB of 1.1 MiB)
Info::
Third-party blocking time is low (0 ms)
68%
32%
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 (211 KB)
PASS
12 fonts (211 KB)
Info::
12 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

12

211 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 500 ms 1.0 s 1.5 s FCP 909 ms LCP 1.7 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://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://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/v13/7cHqv4kjgoGqM7E30-8s51ostz0rdg.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
7cHpv4kjgoGqM7E_DMs5yng... 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
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
Network Waterfall
46 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
20% of JavaScript execution is third-party
First-party Third-party 182ms · 97KB · €2/mo
admin-pipeline.upsun-fr-3.observability-pipeline.blackfire.io
Other
Optional
Execution 109ms
Transfer 97 KB
Unused 33%
Monthly Cost €1/mo
Unattributable
Other
Optional
Execution 73ms
Transfer 0 KB
Monthly Cost €1/mo

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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