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Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
91
GRADE
A
FIX
2
REVIEW
1
PASS
11
INFO
2

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

Mobile Desktop
81
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
91
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
92
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
50
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.

961 ms

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

2.70 s

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

609 ms

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

0.002

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

972 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.

2.94 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
16
11 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 (369.4 KiB of 454.5 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
1280ms total JS execution
REVIEW
1280ms total JS execution
Warning::
https://www.codecademy.com/cdn-cgi/challenge-platf...: 1020ms CPU time
Info::
Unattributable: 186ms CPU time
Info::
https://www.codecademy.com/: 74ms CPU time
Info::
Third-party scripts: 186ms (15% of total)

Main Thread Breakdown

Script Evaluation 76% Other 16% Garbage Collection 3%
ScriptTotalScriptingParse/CompileParty
https://www.codecademy.com/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9e8bb11cc83d6fb81020ms968ms16ms1st
Unattributable186ms4ms0ms3rd
https://www.codecademy.com/74ms8ms1ms1st
A+
Page Weight Budget
454 KB transferred, 16 requests
PASS
454 KB transferred, 16 requests
Info::
Page weighs 879 KB (454 KB transferred)
Info::
16 HTTP requests
Info::
Estimated 0.09 g CO2 per page load
454 KB / 2.4 MB budget
454 KB transferred
16 requests
0.09 g CO2 per page load
Other 265.9 KiB 59%
HTML 100.4 KiB 22%
JavaScript 85.7 KiB 19%
Other 1.7 KiB 0%
Images 807 B 0%
Other 68 B 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
2 images, 0 KB saveable
PASS
2 images, 0 KB saveable
Info::
All images are well-optimized
2 images 1 KB
0 oversized -0 KB
2 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
7 scripts, 0 KB unused
PASS
7 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.codecademy.com/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9e8bb11cc83d6fb868 KB—✓1st
blob:https://www.codecademy.com/a14c574c-0ed2-4bd5-aad4-12426ed348ba0 KB—✓3rd
https://challenges.cloudflare.com/turnstile/v0/b/625261456364/api.js?onload=OBvX9&render=explicit17 KB—✓3rd
blob:https://www.codecademy.com/75fa7a5a-fac5-4845-b983-1d6757295b63-0 KB—✓3rd
blob:https://challenges.cloudflare.com/07636d3f-808a-4e1f-b10a-6893ed1d258d0 KB—✓3rd
blob:https://challenges.cloudflare.com/7b4801c2-4e71-4f4b-ba8a-cbab40e2c6a7-0 KB—✓3rd
blob:https://challenges.cloudflare.com/7b4801c2-4e71-4f4b-ba8a-cbab40e2c6a7-0 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+
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
16 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
15% of JavaScript execution is third-party
First-party Third-party 186ms · 0KB · $2/mo
Unattributable
Other
Optional
Execution 186ms
Transfer 0 KB
Monthly Cost $2/mo

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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