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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
75
GRADE
C
FIX
2
REVIEW
3
PASS
7
INFO
2

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

Mobile Desktop
49
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
97
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.

1.44 s

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

3.41 s

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

475 ms

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

0.048

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

3.07 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.

5.82 s

Page Load Progression

825 ms
1.7 s
2.5 s
3.3 s
4.1 s
5.0 s
5.8 s
6.6 s
Checks
14
7 PASS 3 REVIEW 2 FIX
F
Page Weight Budget
Action
5.4 MB transferred, 222 requests
FIX
5.4 MB transferred, 222 requests
Critical::
Page weighs 19.7 MB (5.4 MB transferred)
Warning::
JavaScript is 3.5 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 3.5 MB
Info::
CSS is 232 KB — consider purging unused styles
Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.
Got: 232 KB
Warning::
222 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 1.1 g CO2 per page load
5.4 MB / 2.4 MB budget
5.4 MB transferred
222 requests
1.1 g CO2 per page load
JavaScript 3.5 MiB 65%
Other 548.1 KiB 10%
HTML 500.5 KiB 9%
Other 284.2 KiB 5%
CSS 232.2 KiB 4%
Images 216.6 KiB 4%
Fonts 150.8 KiB 3%
Other 3.9 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

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

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 Bundles
Action
161 scripts, 1.5 MB unused
FIX
161 scripts, 1.5 MB unused
Warning::
https://www.doctolib.fr/rspack/36034-f29682f219107...: 196 KB unused (73%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.doctolib.fr/rspack/10764-998027801972b...: 184 KB unused (89%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.doctolib.fr/rspack/js/39541-b7694629f8...: 159 KB unused (52%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.doctolib.fr/rspack/26195-1d70c3b36a530...: 128 KB unused (52%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.doctolib.fr/rspack/21141-46b97a0872f23...: 117 KB unused (95%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 1.5 MB
1512 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.doctolib.fr/rspack/36034-f29682f21910766c.js270 KB196 KB (73%)✓1st
https://www.doctolib.fr/rspack/10764-998027801972b4db.js208 KB184 KB (89%)✓1st
https://www.doctolib.fr/rspack/js/39541-b7694629f8780cde.chunk.js309 KB159 KB (52%)✓1st
https://www.doctolib.fr/rspack/26195-1d70c3b36a5306af.js248 KB128 KB (52%)✓1st
https://www.doctolib.fr/rspack/21141-46b97a0872f236fc.js123 KB117 KB (95%)✓1st
https://assets.doctolib.fr/static_webpack/sentry-7ca06c94a727794a.js133 KB107 KB (80%)✓3rd
https://www.doctolib.fr/rspack/83459-ee8fea544a733ab9.js81 KB76 KB (94%)✓1st
https://www.doctolib.fr/rspack/js/94789-43430e7eaf9b82b6.chunk.js87 KB69 KB (80%)✓1st
https://assets.doctolib.fr/rspack/38358-109fba4f2c44bd94.js125 KB65 KB (52%)✓3rd
https://www.doctolib.fr/rspack/90542-315cb7126ca8a20e.js77 KB60 KB (79%)✓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

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
Image Optimization
Action
18 images, 0 KB saveable
REVIEW
18 images, 0 KB saveable
Warning::
https://www.doctolib.fr/rspack/89445a7a32b87f02.pn... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.doctolib.fr/rspack/faa21d0cfa490633.we... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://assets.doctolib.fr/img/patient/homepage/b_... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.doctolib.fr/rspack/ce38df5c086a2d71.we... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.doctolib.fr/rspack/664d75bfddbc37ec.we... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://assets.doctolib.fr/img/cms/logo-blue.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://assets.doctolib.fr/img/homepage/hp-google-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.doctolib.fr/rspack/8a95e5cdf4bbfee1.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.doctolib.fr/rspack/f323e54f672f098e.pn... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.doctolib.fr/rspack/1d2915b785bb56c6.we... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.doctolib.fr/rspack/4fbe366ca9e68fb1.we... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://assets.doctolib.fr/img/homepage/hp-app-sto... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.doctolib.fr/rspack/6fb057589f3aefde.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.doctolib.fr/rspack/6da930dd4a069e39.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
18 images 217 KB
0 oversized -0 KB
13 legacy format
14 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

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

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

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

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

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

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 Execution Cost
Action
1869ms total JS execution
REVIEW
1869ms total JS execution
Warning::
Unattributable: 497ms CPU time
Warning::
https://www.doctolib.fr/rspack/26195-1d70c3b36a530...: 356ms CPU time
Warning::
https://www.doctolib.fr/: 343ms CPU time
Warning::
https://www.doctolib.fr/rspack/js/39541-b7694629f8...: 330ms CPU time
Warning::
https://assets.doctolib.fr/static_webpack/rum-data...: 289ms CPU time
Info::
Third-party scripts: 839ms (45% of total)

Main Thread Breakdown

Script Evaluation 47% Script Parsing & Compilation 22% Other 18% Style & Layout 6% Garbage Collection 3% Parse HTML & CSS 3%
ScriptTotalScriptingParse/CompileParty
Unattributable497ms32ms0ms3rd
https://www.doctolib.fr/rspack/26195-1d70c3b36a5306af.js356ms277ms71ms1st
https://www.doctolib.fr/343ms38ms69ms1st
https://www.doctolib.fr/rspack/js/39541-b7694629f8780cde.chunk.js330ms293ms36ms1st
https://assets.doctolib.fr/static_webpack/rum-datadog-c577014dd3dffb96a37d.js289ms271ms6ms3rd
https://browser.sentry-cdn.com/6.19.7/bundle.min.js54ms28ms2ms3rd
B
HTTP Caching
max-age=0, private, must-revalidate
REVIEW
max-age=0, private, must-revalidate
Info::
Cache-Control header is set
Got: max-age=0, private, must-revalidate
Info::
ETag present — enables conditional (304) responses
Cache-Control

max-age=0, private, must-revalidate

DirectiveValueMeaning
max-age0Cache for 0 seconds
private—Only browser cache, not CDN/proxy
must-revalidate—Must recheck with server after expiry
A
Third-Party Impact
23% third-party, 0 ms blocking
PASS
23% third-party, 0 ms blocking
Info::
Third-party code accounts for 23% of page weight (1.2 MiB of 5.4 MiB)
Info::
Third-party blocking time is low (0 ms)
77%
23%
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
4 fonts (151 KB)
PASS
4 fonts (151 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

4

151 KB total

Render-blocking

0

of 4

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 FCP 1.4 s LCP 3.4 shttps://assets.doctolib.fr/fonts/font-roboto-regular.ttffont-roboto-regular.ttf https://assets.doctolib.fr/fonts/font-roboto-regular.ttf — 35.1 KiB — 0 ms — font-display: swaphttps://assets.doctolib.fr/fonts/font-roboto-bold.ttffont-roboto-bold.ttf https://assets.doctolib.fr/fonts/font-roboto-bold.ttf — 35.1 KiB — 0 ms — font-display: swaphttps://assets.doctolib.fr/fonts/font-montserrat-bold.ttffont-montserrat-bold.ttf https://assets.doctolib.fr/fonts/font-montserrat-bold.ttf — 45.3 KiB — 0 ms — font-display: swaphttps://assets.doctolib.fr/fonts/font-roboto-medium.ttffont-roboto-medium.ttf https://assets.doctolib.fr/fonts/font-roboto-medium.ttf — 35.3 KiB — 0 ms — font-display: swap
font-roboto-regular.ttf ttf swap
Size 35 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
font-roboto-bold.ttf ttf swap
Size 35 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
font-montserrat-bold.ttf ttf swap
Size 45 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
font-roboto-medium.ttf ttf swap
Size 35 KB
Load time 0 ms
Start 0 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 ~45 KB and ~90 ms

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+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

Network Waterfall
222 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
45% of JavaScript execution is third-party
First-party Third-party 839ms · 72KB · €9/mo
Unattributable
Other
Costly
Execution 497ms
Transfer 0 KB
Monthly Cost €5/mo
assets.doctolib.fr
Other
Costly
Execution 289ms
Transfer 51 KB
Unused 45%
Monthly Cost €3/mo
browser.sentry-cdn.com
Other
Optional
Execution 54ms
Transfer 21 KB
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • Unattributable adds 497ms and costs ~€5/month
  • assets.doctolib.fr adds 289ms and costs ~€3/month

45% 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 497ms 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

assets.doctolib.fr takes 289ms 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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