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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
72
GRADE
C
FIX
3
REVIEW
3
PASS
6
INFO
2

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

Mobile Desktop
87
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
78
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
81
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.

993 ms

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

1.01 s

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

137 ms

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

0.046

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

2.97 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.

4.12 s

Page Load Progression

843 ms
1.7 s
2.5 s
3.4 s
4.2 s
5.1 s
5.9 s
6.7 s
Checks
14
6 PASS 3 REVIEW 3 FIX
F
Page Weight Budget
Action
5.1 MB transferred, 119 requests
FIX
5.1 MB transferred, 119 requests
Critical::
Page weighs 15.5 MB (5.1 MB transferred)
Warning::
JavaScript is 1.2 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.2 MB
Warning::
119 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
5.1 MB / 2.4 MB budget
5.1 MB transferred
119 requests
1.1 g CO2 per page load
Other 2.9 MiB 56%
JavaScript 1.2 MiB 23%
Images 653.3 KiB 12%
Fonts 149.3 KiB 3%
CSS 99.4 KiB 2%
Other 88.0 KiB 2%
HTML 66.1 KiB 1%
Other 5.7 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

D
Third-Party Impact
Action
81% third-party, 0 ms blocking
FIX
81% third-party, 0 ms blocking
Warning::
Third-party code accounts for 81% of page weight (4.2 MiB of 5.1 MiB)
Info::
Third-party blocking time is low (0 ms)
19%
81%
First-party Third-party
F
JS Bundles
Action
44 scripts, 554 KB unused
FIX
44 scripts, 554 KB unused
Warning::
https://www.whoop.com/_next/static/chunks/689-8849...: 274 KB unused (84%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-NGF...: 61 KB unused (44%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.lightboxcdn.com/vendor/7206db4b-ab9c-4...: 60 KB unused (52%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.lightboxcdn.com/vendor/7206db4b-ab9c-4...: 43 KB unused (64%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.lightboxcdn.com/vendor/7206db4b-ab9c-4...: 43 KB unused (64%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 554 KB
554 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.whoop.com/_next/static/chunks/689-8849113a05230344.js328 KB274 KB (84%)✓1st
https://www.googletagmanager.com/gtm.js?id=GTM-NGFF9PP139 KB61 KB (44%)✓3rd
https://www.lightboxcdn.com/vendor/7206db4b-ab9c-4386-85b5-d82a8940401a/main.js?cb=11F269417CC438CF09843839F630DC61116 KB60 KB (52%)✓3rd
https://www.lightboxcdn.com/vendor/7206db4b-ab9c-4386-85b5-d82a8940401a/lightbox_builder.js?cb=F96ACFC6CCCE1091C48E3BD493FEDB430 KB43 KB (64%)✓3rd
https://www.lightboxcdn.com/vendor/7206db4b-ab9c-4386-85b5-d82a8940401a/lightbox_builder.js?cb=F96ACFC6CCCE1091C48E3BD493FEDB4367 KB43 KB (64%)✓3rd
https://www.whoop.com/_next/static/chunks/app/%5Bregion%5D/%5Blocale%5D/%5B...slug%5D/page-d3feb99a95c96d6c.js67 KB39 KB (58%)✓1st
https://www.whoop.com/_next/static/chunks/318-e9fc07735cb3de9c.js47 KB35 KB (76%)✓1st
https://www.whoop.com/_next/static/chunks/app/%5Bregion%5D/%5Blocale%5D/%5B...slug%5D/error-072e89baa3d15edf.js2 KB—✓1st
https://www.whoop.com/_next/static/chunks/main-app-fbd57abeeb9345e7.js1 KB—✓1st
https://www.whoop.com/_next/static/chunks/307-18564835794782dc.js26 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

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
JS Execution Cost
Action
1872ms total JS execution
REVIEW
1872ms total JS execution
Warning::
Unattributable: 382ms CPU time
Warning::
https://www.whoop.com/fr/en/: 372ms CPU time
Warning::
https://www.whoop.com/_next/static/chunks/935-81a2...: 357ms CPU time
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-NGF...: 253ms CPU time
Info::
https://cdn.amplitude.com/libs/analytics-browser-2...: 113ms CPU time
Info::
Third-party scripts: 900ms (48% of total)

Main Thread Breakdown

Script Evaluation 52% Other 21% Script Parsing & Compilation 12% Style & Layout 7% Parse HTML & CSS 4%
ScriptTotalScriptingParse/CompileParty
Unattributable382ms56ms0ms3rd
https://www.whoop.com/fr/en/372ms52ms81ms1st
https://www.whoop.com/_next/static/chunks/935-81a2d84af5610b1e.js357ms308ms4ms1st
https://www.googletagmanager.com/gtm.js?id=GTM-NGFF9PP253ms233ms13ms3rd
https://cdn.amplitude.com/libs/analytics-browser-2.10.0-min.js.gz113ms95ms17ms3rd
https://www.whoop.com/_next/static/chunks/689-8849113a05230344.js111ms66ms45ms1st
https://www.lightboxcdn.com/vendor/7206db4b-ab9c-4386-85b5-d82a8940401a/main.js?cb=11F269417CC438CF09843839F630DC6176ms33ms10ms3rd
https://www.lightboxcdn.com/vendor/7206db4b-ab9c-4386-85b5-d82a8940401a/custom_box.js?cb=E31AE4E9BD9D72141647E36CE7B927FB76ms70ms2ms3rd
https://www.whoop.com/_next/static/chunks/b6cf391a-1cc14d6d1d37aa64.js71ms8ms1ms1st
https://www.whoop.com/_next/static/chunks/bce60fc1-13549079f3adf78e.js61ms30ms5ms1st
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

B
HTTP Caching
public, max-age=0, must-revalidate
REVIEW
public, max-age=0, must-revalidate
Info::
Cache-Control header is set
Got: public, max-age=0, must-revalidate
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

public, max-age=0, must-revalidate

DirectiveValueMeaning
public—Any cache may store this response
max-age0Cache for 0 seconds
must-revalidate—Must recheck with server after expiry
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
Image Optimization
22 images, 0 KB saveable
PASS
22 images, 0 KB saveable
Info::
All images are well-optimized
22 images 602 KB
0 oversized -0 KB
2 legacy format
0 missing dimensions CLS risk
A+
Font Loading
15 fonts (149 KB)
PASS
15 fonts (149 KB)
Info::
15 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

15

149 KB total

Render-blocking

0

of 15

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s FCP 993 ms LCP 1.0 shttps://use.typekit.net/af/efe4a5/00000000000000007735e609/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n4&v=3l https://use.typekit.net/af/efe4a5/00000000000000007735e609/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n4&v=3 — 29.3 KiB — 0 ms — font-display: swaphttps://use.typekit.net/af/78aca8/00000000000000007735e60d/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n6&v=3l https://use.typekit.net/af/78aca8/00000000000000007735e60d/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n6&v=3 — 29.3 KiB — 0 ms — font-display: swaphttps://use.typekit.net/af/2555e1/00000000000000007735e603/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n7&v=3l https://use.typekit.net/af/2555e1/00000000000000007735e603/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n7&v=3 — 30.2 KiB — 0 ms — font-display: swaphttps://use.typekit.net/af/23e139/00000000000000007735e605/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n5&v=3l https://use.typekit.net/af/23e139/00000000000000007735e605/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n5&v=3 — 30.0 KiB — 0 ms — font-display: swaphttps://use.typekit.net/af/144da4/00000000000000007735e619/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=i6&v=3l https://use.typekit.net/af/144da4/00000000000000007735e619/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=i6&v=3 — 30.5 KiB — 0 ms — font-display: swaphttps://use.typekit.net/af/2555e1/00000000000000007735e603/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n7&v=3l https://use.typekit.net/af/2555e1/00000000000000007735e603/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n7&v=3 — 0 B — 0 ms — font-display: swaphttps://use.typekit.net/af/78aca8/00000000000000007735e60d/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n6&v=3l https://use.typekit.net/af/78aca8/00000000000000007735e60d/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n6&v=3 — 0 B — 0 ms — font-display: swaphttps://use.typekit.net/af/144da4/00000000000000007735e619/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=i6&v=3l https://use.typekit.net/af/144da4/00000000000000007735e619/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=i6&v=3 — 0 B — 0 ms — font-display: swaphttps://use.typekit.net/af/efe4a5/00000000000000007735e609/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n4&v=3l https://use.typekit.net/af/efe4a5/00000000000000007735e609/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n4&v=3 — 0 B — 0 ms — font-display: swaphttps://use.typekit.net/af/23e139/00000000000000007735e605/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n5&v=3l https://use.typekit.net/af/23e139/00000000000000007735e605/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n5&v=3 — 0 B — 0 ms — font-display: swaphttps://use.typekit.net/af/2555e1/00000000000000007735e603/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n7&v=3l https://use.typekit.net/af/2555e1/00000000000000007735e603/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n7&v=3 — 0 B — 0 ms — font-display: swaphttps://use.typekit.net/af/78aca8/00000000000000007735e60d/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n6&v=3l https://use.typekit.net/af/78aca8/00000000000000007735e60d/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n6&v=3 — 0 B — 0 ms — font-display: swaphttps://use.typekit.net/af/144da4/00000000000000007735e619/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=i6&v=3l https://use.typekit.net/af/144da4/00000000000000007735e619/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=i6&v=3 — 0 B — 0 ms — font-display: swaphttps://use.typekit.net/af/efe4a5/00000000000000007735e609/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n4&v=3l https://use.typekit.net/af/efe4a5/00000000000000007735e609/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n4&v=3 — 0 B — 0 ms — font-display: swaphttps://use.typekit.net/af/23e139/00000000000000007735e605/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n5&v=3l https://use.typekit.net/af/23e139/00000000000000007735e605/30/l?primer=7cdcb44be4a7db8877ffa5c0007b8dd865b3bbc383831fe2ea177f62257a9191&fvd=n5&v=3 — 0 B — 0 ms — font-display: swap
l woff2 swap
Size 29 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 29 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 30 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 30 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 30 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
l 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
Network Waterfall
119 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
48% of JavaScript execution is third-party
First-party Third-party 900ms · 292KB · €5/mo
Unattributable
Other
Costly
Execution 382ms
Transfer 0 KB
Monthly Cost €2/mo
Google Tag Manager
Tag Manager
Costly
Execution 253ms
Transfer 139 KB
Unused 44%
Monthly Cost €1/mo
Amplitude
Analytics
Optional
Execution 113ms
Transfer 37 KB
Monthly Cost €1/mo
www.lightboxcdn.com
Other
Optional
Execution 76ms
Transfer 116 KB
Unused 52%
Monthly Cost €0/mo
www.lightboxcdn.com
Other
Optional
Execution 76ms
Transfer 0 KB
Monthly Cost €0/mo

These scripts may cost more than they're worth

  • Unattributable adds 382ms and costs ~€2/month
  • Google Tag Manager adds 253ms and costs ~€1/month

48% 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 382ms 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

Google Tag Manager takes 253ms 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

52% of www.lightboxcdn.com'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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