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https://icloud.com

Performance

· 22 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
75
GRADE
C
FIX
4
REVIEW
6
PASS
9
INFO
3

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

Mobile Desktop
78
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
100
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
88
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.

462 ms

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

2.48 s

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

243 ms

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

0.000

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

781 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.

2.49 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
22
9 PASS 6 REVIEW 4 FIX
F
Page Weight Budget
Action
3.3 MB transferred, 27 requests
FIX
3.3 MB transferred, 27 requests
Warning::
Page weighs 7.6 MB (3.3 MB transferred)
Warning::
JavaScript is 907 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 907 KB
Info::
27 HTTP requests
Info::
Estimated 0.70 g CO2 per page load
3.3 MB / 2.4 MB budget
3.3 MB transferred
27 requests
0.70 g CO2 per page load
Other 1.6 MiB 48%
JavaScript 906.9 KiB 27%
Other 477.7 KiB 14%
Images 320.9 KiB 9%
CSS 73.8 KiB 2%
HTML 11.1 KiB 0%
Other 3.0 KiB 0%
Other 1.1 KiB 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

D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (3.3 MiB of 3.3 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Bundles
Action
7 scripts, 582 KB unused
FIX
7 scripts, 582 KB unused
Warning::
https://www.icloud.com/system/icloud.com/2618Build...: 515 KB unused (67%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.icloud.com/system/icloud.com/2618Build...: 66 KB unused (74%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.icloud.com/system/icloud.com/2618Build...: unminified — 29 KB could be saved
Warning::
https://www.icloud.com/system/icloud.com/2618Build...: unminified — 8 KB could be saved
Info::
Total unused JavaScript: 582 KB
582 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.icloud.com/system/icloud.com/2618Build21/en-us/main.js769 KB515 KB (67%)✓3rd
https://www.icloud.com/system/icloud.com/2618Build21/en-us/RootComponentRoute.js91 KB66 KB (74%)✗3rd
blob:https://www.icloud.com/b8aa32a7-b28e-4bde-8926-91f87f7ffc1b0 KB—✓3rd
https://www.icloud.com/system/icloud.com/2618Build21/en-us/vendors~RootComponentRoute.js33 KB—✗3rd
https://appleid.cdn-apple.com/appleauth/static/jsapi/authService.latest.min.js15 KB—✓3rd
https://www.icloud.com/system/icloud.com/2618Build21/en-us/vendors~Routes-HomePageRoute.js347 KB—✓3rd
https://www.icloud.com/system/icloud.com/2618Build21/en-us/Routes-HomePageRoute.js128 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

F
Page Weight Inventory
Action
27 resources · 3.3 MB · 582 KB savings available
FIX
27 resources · 3.3 MB · 582 KB savings available
Warning::
Page weight 3.3 MB exceeds 1 MB target by 2.3 MB
Got: 3.3 MB Expected: ≤ 1 MB
Info::
~582 KB of savings available
Warning::
26 third-party resources (100% of weight)
Info::
4 resources over 200KB
27 resources · 3.3 MiB · 26 third-party 2.3 MiB over 1MB target
Media 48% · 1.6 MiB
JavaScript 40% · 1.3 MiB
Image 9% · 323.3 KiB
CSS 2% · 73.8 KiB
Document 0% · 11.1 KiB
Other 0% · 4.5 KiB

~581.9 KiB of savings available

Remove unused JavaScript: 581.9 KiB
B
Image Optimization
7 images, 0 KB saveable
REVIEW
7 images, 0 KB saveable
Info::
All images are well-optimized
7 images 321 KB
0 oversized -0 KB
5 legacy format
0 missing dimensions CLS risk
B
HTTP/3 (QUIC)
HTTP/3 not advertised
REVIEW
HTTP/3 not advertised
Info::
HTTP/3 (QUIC) is not advertised
HTTP/3 isn't advertised via Alt-Svc and the worker didn't negotiate h3. HTTP/3 reduces handshake latency (1-RTT instead of 2-3 RTTs) and is more resilient on lossy connections. Most modern CDNs (Cloudflare, Fastly, AWS CloudFront, Google Cloud CDN) support HTTP/3 with a single config switch -- consider enabling for mobile-heavy workloads.
C
Compression Algorithm
Action
Main response served uncompressed
REVIEW
Main response served uncompressed
Info::
Main HTML response has no Content-Encoding (uncompressed)
The main HTML document is served without compression. The Text Compression section above lists the broader picture; for the main response specifically, even gzip would shave ~70-80% off most text payloads.
B
Main HTML Cache-Control
Main HTML max-age=3600 (~60min)
REVIEW
Main HTML max-age=3600 (~60min)
Info::
Main HTML cached for 60 minutes -- mild staleness risk
Got: max-age=3600
B
Server-Timing Observability
No Server-Timing header found
REVIEW
No Server-Timing header found
Info::
No Server-Timing header found
Server-Timing exposes backend timing breakdowns to browser DevTools (e.g., `db: 45ms; render: 120ms; cache: 2ms`). Useful for diagnosing slow pages without backend log access. Most modern frameworks (Next.js, Cloudflare Workers, Fastly) emit it automatically; absence on a managed platform usually means telemetry headers are stripped at the edge.
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

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+
JS Execution Cost
478ms total JS execution
PASS
478ms total JS execution
Warning::
https://www.icloud.com/system/icloud.com/2618Build...: 334ms CPU time
Info::
https://www.icloud.com/: 79ms CPU time
Info::
Unattributable: 66ms CPU time
Warning::
Third-party scripts: 413ms (86% of total)

Main Thread Breakdown

Script Evaluation 51% Script Parsing & Compilation 21% Other 16% Style & Layout 6% Parse HTML & CSS 3%
ScriptTotalScriptingParse/CompileParty
https://www.icloud.com/system/icloud.com/2618Build21/en-us/main.js334ms236ms91ms3rd
https://www.icloud.com/79ms16ms2ms3rd
Unattributable66ms5ms0ms1st
A+
Font Loading
No web fonts (system fonts)
PASS
No web fonts (system fonts)
Info::
No web fonts loaded — system fonts are fastest
No web fonts loaded — system fonts are optimal.
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+
LCP Image Preload
LCP preload audit not available
PASS
LCP preload audit not available
Info::
LCP image preload audit not available for this scan
A+
Server Response Intelligence
1 server-response signal(s) detected
PASS
1 server-response signal(s) detected
Info::
No `ETag` or `Last-Modified` -- conditional GET not supported
Without either header, browsers can't issue conditional GETs and refresh always re-downloads the full response body even when nothing changed. Add `ETag: "<hash>"` (or `Last-Modified: <date>`) on cacheable responses; the server returns 304 Not Modified when the client's cached copy is still valid, saving bandwidth.
A
HTTP Caching
max-age=3600 (1 hour)
PASS
max-age=3600 (1 hour)
Info::
Cache-Control header is set
Got: max-age=3600
Info::
Effective TTL: 1 hour (max-age=3600)
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

max-age=3600

DirectiveValueMeaning
max-age3600Cache for 1 hour
Effective TTL: 3600 seconds
Network Waterfall
27 requests over 594ms
INFO
0 ms 500 ms 1.0 s 1.5 s 2.0 s 2.5 s FCP 462 ms LCP 2.5 shttps://icloud.com// https://icloud.com/ — 301 — 376 B — 7 ms — h2https://www.icloud.com/www.icloud.com/ https://www.icloud.com/ — 200 — 11.1 KiB — 13 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/en-us/main.jswww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/en-us/main.js — 200 — 768.9 KiB — 56 ms — http/1.1https://setup.icloud.com/setup/ws/1/validate?clientBuildNumber=2618Build21&clientMasteringNumber=2618Build21&clientId=a18f2e95-b107-41d2-9acb-7776f8cc08e4&requestId=6ce381d2-d84b-4bd0-9886-8c342faac8dfsetup.icloud.com/setup/ws/1/validat... https://setup.icloud.com/setup/ws/1/validate?clientBuildNumber=2618Build21&clientMasteringNumber=2618Build21&clientId=a18f2e95-b107-41d2-9acb-7776f8cc08e4&requestId=6ce381d2-d84b-4bd0-9886-8c342faac8df — 421 — 1.4 KiB — 423 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/en-us/main.csswww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/en-us/main.css — 200 — 47.6 KiB — 18 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/en-us/images@1x.binwww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/en-us/images@1x.bin — 200 — 1.1 KiB — 3 ms — http/1.1blob:https://www.icloud.com/b8aa32a7-b28e-4bde-8926-91f87f7ffc1bwww.icloud.com/b8aa32a7-b28e-4bde-8... blob:https://www.icloud.com/b8aa32a7-b28e-4bde-8926-91f87f7ffc1b — -1 — 0 B — 0 ms — https://www.icloud.com/locales/5/en-US.json?clientBuildNumber=2618Build21&clientMasteringNumber=2618Build21&clientId=a18f2e95-b107-41d2-9acb-7776f8cc08e4www.icloud.com/locales/5/en-US.json... https://www.icloud.com/locales/5/en-US.json?clientBuildNumber=2618Build21&clientMasteringNumber=2618Build21&clientId=a18f2e95-b107-41d2-9acb-7776f8cc08e4 — 200 — 1.7 KiB — 17 ms — http/1.1data:image/webp;base64,UklGRiIAAABXRUJQVlA4IBYAAAAwAQCdASoBAAEADsD+JaQAA3AAAAAAdata:image/webp;base64,UklGRiIAAABX... data:image/webp;base64,UklGRiIAAABXRUJQVlA4IBYAAAAwAQCdASoBAAEADsD+JaQAA3AAAAAA — 200 — 0 B — 0 ms — datablob:https://www.icloud.com/f12a4168-7b09-4fac-b074-5026ba8e45f3www.icloud.com/f12a4168-7b09-4fac-b... blob:https://www.icloud.com/f12a4168-7b09-4fac-b074-5026ba8e45f3 — 200 — 0 B — 1 ms — blobdata:text/css;base64,LmJyb3dzZXItbm90aWZpY2F0aW9ucy1zdWNjZXNzLWFsZXJ0IC50aXRsZTo6YmVmb3Jle2JhY2tncm…data:text/css;base64,LmJyb3dzZXItbm... data:text/css;base64,LmJyb3dzZXItbm90aWZpY2F0aW9ucy1zdWNjZXNzLWFsZXJ0IC50aXRsZTo6YmVmb3Jle2JhY2tncm… — 200 — 0 B — 0 ms — datahttps://www.icloud.com/system/icloud.com/2618Build21/en-us/6.main.csswww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/en-us/6.main.css — 200 — 1.4 KiB — 7 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/en-us/vendors~RootComponentRoute.jswww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/en-us/vendors~RootComponentRoute.js — 200 — 33.0 KiB — 19 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/en-us/1.main.csswww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/en-us/1.main.css — 200 — 24.7 KiB — 16 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/en-us/RootComponentRoute.jswww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/en-us/RootComponentRoute.js — 200 — 90.5 KiB — 29 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/wallpaper.svgwww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/wallpaper.svg — 200 — 2.1 KiB — 14 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/wallpaper_dark.svgwww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/wallpaper_dark.svg — 200 — 2.2 KiB — 13 ms — http/1.1https://appleid.cdn-apple.com/appleauth/static/jsapi/authService.latest.min.jsappleid.cdn-apple.com/appleauth/sta... https://appleid.cdn-apple.com/appleauth/static/jsapi/authService.latest.min.js — 200 — 14.5 KiB — 20 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/0e4e931e06552e87f2fdff2832e11bb9.pngwww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/0e4e931e06552e87f2fdff2832e11bb9.png — 200 — 45.9 KiB — 11 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/06b68855764eb0e23f269ed4ef7935f0.pngwww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/06b68855764eb0e23f269ed4ef7935f0.png — 200 — 67.1 KiB — 10 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/7cb9ecdad2b384754de394732519f658.pngwww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/7cb9ecdad2b384754de394732519f658.png — 200 — 203.7 KiB — 17 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/favicons/default-favicon-light-32x32.pngwww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/favicons/default-favicon-light-32x32.png — 200 — 2.4 KiB — 3 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/fpo@1x.mp4www.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/fpo@1x.mp4 — 206 — 1.6 MiB — 45 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/favicons/default-favicon-light-32x32.pngwww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/favicons/default-favicon-light-32x32.png — 200 — 0 B — 2 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/en-us/vendors~Routes-HomePageRoute.jswww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/en-us/vendors~Routes-HomePageRoute.js — 200 — 346.8 KiB — 29 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/en-us/Routes-HomePageRoute.jswww.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/en-us/Routes-HomePageRoute.js — 200 — 128.2 KiB — 22 ms — http/1.1https://www.icloud.com/system/icloud.com/2618Build21/fpo@1x.mp4www.icloud.com/system/icloud.com/26... https://www.icloud.com/system/icloud.com/2618Build21/fpo@1x.mp4 — 206 — 20.4 KiB — 16 ms — http/1.1
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
86% of JavaScript execution is third-party
First-party Third-party 413ms · 780KB · $5/mo
www.icloud.com
Other
Costly
Execution 334ms
Transfer 769 KB
Unused 67%
Monthly Cost $4/mo
www.icloud.com
Other
Optional
Execution 79ms
Transfer 11 KB
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • www.icloud.com adds 334ms and costs ~$4/month

86% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

www.icloud.com takes 334ms 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

67% of www.icloud.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

Image Optimization
4 images, 314 KB total, 183 KB wasted
INFO

Image Optimization Audit

Total Images

4

Total Size

314 KB

Oversized

1

Wasted

183 KB

1 missing alt text 3 missing dimensions 2 missing lazy loading
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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