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https://mskcc.org

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
90
GRADE
A
FIX
2
REVIEW
1
PASS
12
INFO
2

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

Mobile Desktop
84
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
90
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.
40
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.

964 ms

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

1.46 s

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

640 ms

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

0.003

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

1.05 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.

3.12 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
17
12 PASS 1 REVIEW 2 FIX
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 (408.2 KiB of 502.5 KiB)
Info::
Third-party blocking time is low (0 ms)
19%
81%
First-party Third-party
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
JS Execution Cost
Action
1372ms total JS execution
REVIEW
1372ms total JS execution
Warning::
https://mskcc.org/cdn-cgi/challenge-platform/h/b/o...: 1043ms CPU time
Info::
Unattributable: 220ms CPU time
Info::
https://mskcc.org/: 109ms CPU time
Info::
Third-party scripts: 220ms (16% of total)

Main Thread Breakdown

Script Evaluation 72% Other 18% Style & Layout 4% Garbage Collection 3%
ScriptTotalScriptingParse/CompileParty
https://mskcc.org/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f07f3afbab116611043ms978ms16ms1st
Unattributable220ms5ms0ms3rd
https://mskcc.org/109ms17ms2ms1st
A+
Page Weight Budget
502 KB transferred, 19 requests
PASS
502 KB transferred, 19 requests
Info::
Page weighs 897 KB (502 KB transferred)
Info::
19 HTTP requests
Info::
Estimated 0.10 g CO2 per page load
502 KB / 2.4 MB budget
502 KB transferred
19 requests
0.10 g CO2 per page load
Other 308.0 KiB 61%
HTML 96.4 KiB 19%
JavaScript 86.2 KiB 17%
Images 6.8 KiB 1%
Other 3.3 KiB 1%
Other 1.7 KiB 0%
0 2.4 MB 4.9 MB
Under budget
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
3 images, 0 KB saveable
PASS
3 images, 0 KB saveable
Info::
All images are well-optimized
3 images 7 KB
0 oversized -0 KB
3 legacy format
0 missing dimensions CLS risk
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+
JS Bundles
8 scripts, 0 KB unused
PASS
8 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://mskcc.org/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f07f3afbab1166169 KB—✓1st
blob:https://mskcc.org/8bb92ac1-9f94-4b13-8d0e-abc8609acbe80 KB—✓3rd
https://challenges.cloudflare.com/turnstile/v0/b/0b8fb825cb67/api.js?onload=cFRiY3&render=explicit17 KB—✓3rd
blob:https://mskcc.org/4d69d0ac-22c2-4d20-b495-1205797b2655-0 KB—✓3rd
blob:https://challenges.cloudflare.com/965f38f3-a2ee-4e74-8635-a2d183982cd70 KB—✓3rd
blob:https://challenges.cloudflare.com/c66138f8-6993-47e7-8ee3-9ac5919e37c3-0 KB—✓3rd
blob:https://challenges.cloudflare.com/c66138f8-6993-47e7-8ee3-9ac5919e37c3-0 KB—✓3rd
blob:https://challenges.cloudflare.com/050688a1-b1a4-4f08-aff0-6eb821e43e60-0 KB—✓3rd
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
Page Weight Inventory
19 resources · 502 KB · 0 KB savings available
PASS
19 resources · 502 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 502 KB
Warning::
13 third-party resources (81% of weight)
Info::
1 resources over 200KB
19 resources · 502.5 KiB · 13 third-party Within 1MB page-weight target
Other 62% · 309.8 KiB
Document 20% · 99.7 KiB
JavaScript 17% · 86.2 KiB
Image 1% · 6.8 KiB
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
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
19 requests over 2368ms
INFO
0 ms 500 ms 1.0 s 1.5 s 2.0 s FCP 964 ms LCP 1.5 shttps://mskcc.org// https://mskcc.org/ — 307 — 59 B — 68 ms — http/1.1https://mskcc.org// https://mskcc.org/ — 403 — 3.3 KiB — 23 ms — h2https://mskcc.org/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f07f3afbab11661/cdn-cgi/challenge-platform/h/b/orc... https://mskcc.org/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f07f3afbab11661 — 200 — 68.8 KiB — 32 ms — h2blob:https://mskcc.org/8bb92ac1-9f94-4b13-8d0e-abc8609acbe8mskcc.org/8bb92ac1-9f94-4b13-8d0e-a... blob:https://mskcc.org/8bb92ac1-9f94-4b13-8d0e-abc8609acbe8 — -1 — 0 B — 0 ms — https://challenges.cloudflare.com/turnstile/v0/b/0b8fb825cb67/api.js?onload=cFRiY3&render=explicitchallenges.cloudflare.com/turnstile... https://challenges.cloudflare.com/turnstile/v0/b/0b8fb825cb67/api.js?onload=cFRiY3&render=explicit — 200 — 17.4 KiB — 99 ms — h2https://mskcc.org/favicon.ico/favicon.ico https://mskcc.org/favicon.ico — 403 — 5.2 KiB — 23 ms — h2https://mskcc.org/favicon.ico/favicon.ico https://mskcc.org/favicon.ico — 403 — 3.3 KiB — 23 ms — h2https://mskcc.org/cdn-cgi/challenge-platform/h/b/flow/ov1/927531819:1776892371:vVewUlFmas0srb30l10YFlK8gjcJmXL29Dq7B946IKw/9f07f3afbab11661/5P6xlUPLJT4w.1tiImWfk9eHCwp5CxUD1JLFMbNf1KY-1776895756-1.2.1.1-gEAMReLEODLPXsNS.keVfLZa9eLxrXkDu4muehvUd1QE47.JSYBP5s21d3lMRlYp/cdn-cgi/challenge-platform/h/b/flo... https://mskcc.org/cdn-cgi/challenge-platform/h/b/flow/ov1/927531819:1776892371:vVewUlFmas0srb30l10YFlK8gjcJmXL29Dq7B946IKw/9f07f3afbab11661/5P6xlUPLJT4w.1tiImWfk9eHCwp5CxUD1JLFMbNf1KY-1776895756-1.2.1.1-gEAMReLEODLPXsNS.keVfLZa9eLxrXkDu4muehvUd1QE47.JSYBP5s21d3lMRlYp — 200 — 13.5 KiB — 35 ms — h2blob:https://mskcc.org/4d69d0ac-22c2-4d20-b495-1205797b2655mskcc.org/4d69d0ac-22c2-4d20-b495-1... blob:https://mskcc.org/4d69d0ac-22c2-4d20-b495-1205797b2655 — 200 — -1 B — 27 ms — blobhttps://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/turnstile/f/ov2/av0/rch/3xk9r/0x4AAAAAAADnPIDROrmt1Wwj/light/fbE/new/normal?lang=autochallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/turnstile/f/ov2/av0/rch/3xk9r/0x4AAAAAAADnPIDROrmt1Wwj/light/fbE/new/normal?lang=auto — 200 — 93.1 KiB — 100 ms — h3https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/cmg/1challenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/cmg/1 — 200 — 208 B — 21 ms — h3blob:https://challenges.cloudflare.com/965f38f3-a2ee-4e74-8635-a2d183982cd7challenges.cloudflare.com/965f38f3-... blob:https://challenges.cloudflare.com/965f38f3-a2ee-4e74-8635-a2d183982cd7 — -1 — 0 B — 0 ms — https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/flow/ov1/4100900095:1776892373:L0nL67ly3l9VisnM33R_sKjYxQhSpF0B3njDgeQGRpI/9f07f3b2286ff9af/DtPtknAGtvrJCFcDsZ5skPHWXCZ88HfHg7gSVe8NKts-1776895757-1.2.1.1-M7X5zOdozoOUWtxbIb0v1xUlGJLqszB9o_0PuwT9q2YuWGrT7lAYh2KV5fmz8JOMchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/flow/ov1/4100900095:1776892373:L0nL67ly3l9VisnM33R_sKjYxQhSpF0B3njDgeQGRpI/9f07f3b2286ff9af/DtPtknAGtvrJCFcDsZ5skPHWXCZ88HfHg7gSVe8NKts-1776895757-1.2.1.1-M7X5zOdozoOUWtxbIb0v1xUlGJLqszB9o_0PuwT9q2YuWGrT7lAYh2KV5fmz8JOM — 200 — 271.7 KiB — 134 ms — h3blob:https://challenges.cloudflare.com/c66138f8-6993-47e7-8ee3-9ac5919e37c3challenges.cloudflare.com/c66138f8-... blob:https://challenges.cloudflare.com/c66138f8-6993-47e7-8ee3-9ac5919e37c3 — 200 — -1 B — 13 ms — blobhttps://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/d/9f07f3b2286ff9af/1776895757448/Euhu4DyLeZwHB1nchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/d/9f07f3b2286ff9af/1776895757448/Euhu4DyLeZwHB1n — 200 — 1.4 KiB — 22 ms — h3https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/pat/9f07f3b2286ff9af/1776895757448/3ba49c28de2b9f7772e0b960c26f3123225493086faec6c67b479bec7c3c1429/LnDJ14h3yWJbdqychallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/pat/9f07f3b2286ff9af/1776895757448/3ba49c28de2b9f7772e0b960c26f3123225493086faec6c67b479bec7c3c1429/LnDJ14h3yWJbdqy — 401 — 1.7 KiB — 21 ms — h3blob:https://challenges.cloudflare.com/c66138f8-6993-47e7-8ee3-9ac5919e37c3challenges.cloudflare.com/c66138f8-... blob:https://challenges.cloudflare.com/c66138f8-6993-47e7-8ee3-9ac5919e37c3 — 200 — -1 B — 9 ms — blobhttps://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/flow/ov1/4100900095:1776892373:L0nL67ly3l9VisnM33R_sKjYxQhSpF0B3njDgeQGRpI/9f07f3b2286ff9af/DtPtknAGtvrJCFcDsZ5skPHWXCZ88HfHg7gSVe8NKts-1776895757-1.2.1.1-M7X5zOdozoOUWtxbIb0v1xUlGJLqszB9o_0PuwT9q2YuWGrT7lAYh2KV5fmz8JOMchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/flow/ov1/4100900095:1776892373:L0nL67ly3l9VisnM33R_sKjYxQhSpF0B3njDgeQGRpI/9f07f3b2286ff9af/DtPtknAGtvrJCFcDsZ5skPHWXCZ88HfHg7gSVe8NKts-1776895757-1.2.1.1-M7X5zOdozoOUWtxbIb0v1xUlGJLqszB9o_0PuwT9q2YuWGrT7lAYh2KV5fmz8JOM — 200 — 22.8 KiB — 45 ms — h3blob:https://challenges.cloudflare.com/050688a1-b1a4-4f08-aff0-6eb821e43e60challenges.cloudflare.com/050688a1-... blob:https://challenges.cloudflare.com/050688a1-b1a4-4f08-aff0-6eb821e43e60 — 200 — -1 B — 16 ms — blob
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
16% of JavaScript execution is third-party
First-party Third-party 220ms · 0KB · $3/mo
Unattributable
Other
Costly
Execution 220ms
Transfer 0 KB
Monthly Cost $3/mo

These scripts may cost more than they're worth

  • Unattributable adds 220ms and costs ~$3/month

Unattributable takes 220ms 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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