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https://inria.fr

Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.

SCORE

80

GRADE

B

FIX

2

REVIEW

5

PASS

6

INFO

2

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

85

Performance

100

Accessibility

100

Best Practices

92

SEO

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

460 ms

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

2.72 s

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

9 ms

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

0.005

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

883 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

2.73 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

15

6 PASS 5 REVIEW 2 FIX

F

Page Weight Budget

Action

2.9 MB transferred, 105 requests

FIX

2.9 MB transferred, 105 requests

Page weighs 5.3 MB (2.9 MB transferred)

Images are 2.1 MB — compress or use modern formats

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Got: 2.1 MB

Fonts are 207 KB — consider subsetting or using system fonts

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

Got: 207 KB

105 HTTP requests — consider bundling or reducing

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

Estimated 0.61 g CO2 per page load

2.9 MB transferred

105 requests

0.61 g CO2 per page load

Images 2.1 MiB 73%

JavaScript 487.2 KiB 16%

Fonts 206.8 KiB 7%

CSS 79.8 KiB 3%

HTML 22.8 KiB 1%

Other 1.8 KiB 0%

Other 702 B 0%

Other 0 B 0%

0 2.4 MB 4.9 MB

Over budget

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.

Source: web.dev

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

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

D

JS Bundles

Action

39 scripts, 188 KB unused

FIX

39 scripts, 188 KB unused

https://piwik.inria.fr/js/container_jXx4kt38.js: 82 KB unused (52%)

Consider code splitting or tree shaking to reduce unused code.

https://inria.fr/themes/custom/inria/js/script.js?...: 41 KB unused (53%)

Consider code splitting or tree shaking to reduce unused code.

https://inria.fr/themes/custom/inria/js/script.js?...: unminified — 28 KB could be saved

https://piwik.inria.fr/matomo.js: 36 KB unused (54%)

Consider code splitting or tree shaking to reduce unused code.

https://inria.fr/modules/contrib/tacjs/assets/vend...: 29 KB unused (74%)

Consider code splitting or tree shaking to reduce unused code.

https://inria.fr/modules/contrib/tacjs/assets/vend...: unminified — 11 KB could be saved

Total unused JavaScript: 188 KB

188 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://piwik.inria.fr/js/container_jXx4kt38.js	157 KB	82 KB (52%)	✓	3rd
https://inria.fr/themes/custom/inria/js/script.js?tdtruy	77 KB	41 KB (53%)	✗	1st
https://piwik.inria.fr/matomo.js	67 KB	36 KB (54%)	✓	3rd
https://inria.fr/modules/contrib/tacjs/assets/vendor/tarteaucitron.js/tarteaucitron.services.js?v=1.20.0	40 KB	29 KB (74%)	✗	1st
https://inria.fr/themes/custom/inria/js/libs/stickybits.min.js?tdtruy	2 KB	—	✓	1st
https://inria.fr/core/misc/drupalSettingsLoader.js?v=11.3.5	0 KB	—	✓	1st
https://inria.fr/core/misc/drupal.init.js?v=11.3.5	1 KB	—	✓	1st
https://inria.fr/core/misc/debounce.js?v=11.3.5	1 KB	—	✓	1st
https://inria.fr/modules/contrib/jquery_ui/assets/vendor/jquery.ui/ui/version-min.js?v=1.13.2	0 KB	—	✓	1st
https://inria.fr/modules/contrib/jquery_ui/assets/vendor/jquery.ui/ui/keycode-min.js?v=1.13.2	0 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

B

Image Optimization

17 images, 0 KB saveable

REVIEW

17 images, 0 KB saveable

All images are well-optimized

17 images 2.1 MB

0 oversized -0 KB

16 legacy format

0 missing dimensions CLS risk

B

JS Execution Cost

704ms total JS execution

REVIEW

704ms total JS execution

https://inria.fr/fr: 317ms CPU time

Unattributable: 201ms CPU time

https://inria.fr/themes/custom/inria/js/script.js?...: 186ms CPU time

Third-party scripts: 201ms (29% of total)

Main Thread Breakdown

Script Evaluation 30% Other 28% Style & Layout 24% Script Parsing & Compilation 7% Parse HTML & CSS 6% Rendering 4%

Script	Total	Scripting	Parse/Compile	Party
https://inria.fr/fr	317ms	13ms	1ms	1st
Unattributable	201ms	9ms	0ms	3rd
https://inria.fr/themes/custom/inria/js/script.js?tdtruy	186ms	136ms	17ms	1st

C

Page Weight Inventory

Action

105 resources · 2.9 MB · 188 KB savings available

REVIEW

105 resources · 2.9 MB · 188 KB savings available

Page weight 1.9 MB over 1MB target

Got: 2.9 MB Expected: ≤ 1 MB

~188 KB of savings available

7 third-party resources (8% of weight)

2 resources over 200KB

105 resources · 2.9 MiB · 7 third-party 1.9 MiB over 1MB target

Image 73% · 2.1 MiB

JavaScript 16% · 487.2 KiB

Font 7% · 206.8 KiB

CSS 3% · 79.8 KiB

Document 1% · 23.1 KiB

Other 0% · 702 B

~187.9 KiB of savings available

Remove unused JavaScript: 187.9 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

105 resources			2.9 MiB

C

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

B

HTTP Caching

must-revalidate, no-cache, private

REVIEW

must-revalidate, no-cache, private

Cache-Control header is set

Got: must-revalidate, no-cache, private

No ETag or Last-Modified header

Conditional requests (304 Not Modified) are not possible without validators.

Cache-Control

must-revalidate, no-cache, private

Directive	Value	Meaning
must-revalidate	—	Must recheck with server after expiry
no-cache	—	Cache but always revalidate first
private	—	Only browser cache, not CDN/proxy

A+

Third-Party Impact

8% third-party, 0 ms blocking

PASS

8% third-party, 0 ms blocking

Third-party code accounts for 8% of page weight (230.4 KiB of 2.9 MiB)

Third-party blocking time is low (0 ms)

92%

First-party Third-party

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are compressed

All text resources are properly compressed.

A+

Font Loading

6 fonts (207 KB)

PASS

6 fonts (207 KB)

6 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

6

207 KB total

Render-blocking

0

of 6

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

InriaSans-Regular.woff woff swap

Size 33 KB

Load time 108 ms

Start 479 ms

Risk FOUT — text flashes from fallback to web font

Convert to woff2 for ~30% smaller file size

InriaSerif-Regular.woff woff swap

Size 39 KB

Load time 112 ms

Start 479 ms

Risk FOUT — text flashes from fallback to web font

Convert to woff2 for ~30% smaller file size

InriaSans-Bold.woff woff swap

Size 32 KB

Load time 112 ms

Start 480 ms

Risk FOUT — text flashes from fallback to web font

Convert to woff2 for ~30% smaller file size

InriaSerif-Bold.woff woff swap

Size 36 KB

Load time 118 ms

Start 480 ms

Risk FOUT — text flashes from fallback to web font

Convert to woff2 for ~30% smaller file size

InriaSans-Italic.woff woff swap

Size 35 KB

Load time 118 ms

Start 481 ms

Risk FOUT — text flashes from fallback to web font

Convert to woff2 for ~30% smaller file size

InriaSans-Light.woff woff swap

Size 32 KB

Load time 120 ms

Start 481 ms

Risk FOUT — text flashes from fallback to web font

Convert to woff2 for ~30% smaller file size

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 ~62 KB and ~124 ms

A+

Resource Caching

All resources properly cached

PASS

All resources properly cached

No caching issues found

All static resources have appropriate caching headers.

A+

Critical Rendering Path

No render-blocking resources

PASS

No render-blocking resources

No render-blocking resources detected

A+

Resource Hints

No optimization needed

PASS

No optimization needed

No resource hint issues

Network Waterfall

105 requests over 1138ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Third-Party Script Cost

Per-script blocking time, transfer cost, and cache headers

INFO

29% of JavaScript execution is third-party

First-party Third-party 201ms · 0KB · €2/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
Unattributable Unattributable	Other	201ms	0 KB	—	€2/mo	Costly

Unattributable

Other

Costly

Execution 201ms

Transfer 0 KB

Monthly Cost €2/mo

These scripts may cost more than they're worth

Unattributable adds 201ms and costs ~€2/month

Unattributable takes 201ms 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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