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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
74
GRADE
C
FIX
4
REVIEW
2
PASS
6
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.
88
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.
92
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.

1.75 s

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

1.99 s

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

81 ms

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

0.055

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

1.84 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.

3.99 s

Page Load Progression

689 ms
1.4 s
2.1 s
2.8 s
3.4 s
4.1 s
4.8 s
5.5 s
Checks
14
6 PASS 2 REVIEW 4 FIX
F
Page Weight Budget
Action
8.3 MB transferred, 94 requests
FIX
8.3 MB transferred, 94 requests
Critical::
Page weighs 15.5 MB (8.3 MB transferred)
Warning::
Images are 6.1 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 6.1 MB
Warning::
JavaScript is 1.9 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.9 MB
Info::
94 HTTP requests
Info::
Estimated 1.7 g CO2 per page load
8.3 MB / 2.4 MB budget
8.3 MB transferred
94 requests
1.7 g CO2 per page load
Images 6.1 MiB 74%
JavaScript 1.9 MiB 23%
Fonts 166.8 KiB 2%
CSS 77.3 KiB 1%
HTML 27.8 KiB 0%
Other 4.7 KiB 0%
Other 4.1 KiB 0%
Other 1.5 KiB 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.

Source: web.dev

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 (8.3 MiB of 8.3 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Bundles
Action
25 scripts, 641 KB unused
FIX
25 scripts, 641 KB unused
Warning::
https://cpwebassets.codepen.io/assets/packs/js/ven...: 424 KB unused (64%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cpwebassets.codepen.io/assets/packs/js/6-7...: 218 KB unused (65%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 641 KB
641 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://cpwebassets.codepen.io/assets/packs/js/vendor-9a4e874746c7ba6cb4f7.chunk.js660 KB424 KB (64%)✓3rd
https://cpwebassets.codepen.io/assets/packs/js/6-71433d627ed09ffe0e50.chunk.js334 KB218 KB (65%)✓3rd
https://cdn.jsdelivr.net/npm/three@0.128.0/examples/js/libs/fflate.min.js12 KB—✓3rd
https://cpwebassets.codepen.io/assets/common/stopExecutionOnTimeout-f07739098a39bd4e74ddd974652dac904146f33fdc1ecab356e8c809a05faccb.js0 KB—✓3rd
https://cpwebassets.codepen.io/assets/packs/js/referrer-tracking-5d275cb3ce20c0c5d483.js1 KB—✓3rd
https://cpwebassets.codepen.io/assets/packs/js/Homepage-Anon-8f60905145f01773ec50.chunk.js6 KB—✓3rd
https://codepen.io/cdn-cgi/challenge-platform/h/b/scripts/jsd/625261456364/main.js?12 KB—✓3rd
https://cdn.carbonads.com/carbon.js?serve=CK7IVK7U&placement=codepenio11 KB—✓3rd
https://srv.buysellads.com/ads/CEAICKQN.json?callback=customJSONPCallback1 KB—✓3rd
https://cdn.jsdelivr.net/npm/three@0.128.0/examples/js/controls/OrbitControls.js6 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
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
Image Optimization
Action
37 images, 0 KB saveable
REVIEW
37 images, 0 KB saveable
Warning::
https://cpwebassets.codepen.io/assets/packs/editor... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/editor... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/airbnb... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/micros... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/ibm-c6... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://static4.buysellads.net/uu/7/173968/1774279... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/grubhu... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/lyft-8... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/editor... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/netfli... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/editor... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/editor... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/adobe-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/salesf... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/icon-b... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://static4.buysellads.net/uu/7/173968/1774279... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/editor... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/square... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/icon-l... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cpwebassets.codepen.io/assets/packs/icon-s... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
37 images 6.1 MB
0 oversized -0 KB
29 legacy format
20 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

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
1297ms total JS execution
REVIEW
1297ms total JS execution
Warning::
https://codepen.io/: 497ms CPU time
Warning::
https://cpwebassets.codepen.io/assets/packs/js/ven...: 396ms CPU time
Info::
Unattributable: 169ms CPU time
Info::
https://cpwebassets.codepen.io/assets/packs/js/eve...: 151ms CPU time
Info::
https://codepen.io/cdn-cgi/challenge-platform/scri...: 84ms CPU time
Warning::
Third-party scripts: 1297ms (100% of total)

Main Thread Breakdown

Script Evaluation 39% Other 32% Style & Layout 14% Script Parsing & Compilation 8% Rendering 5%
ScriptTotalScriptingParse/CompileParty
https://codepen.io/497ms9ms0ms3rd
https://cpwebassets.codepen.io/assets/packs/js/vendor-9a4e874746c7ba6cb4f7.chunk.js396ms287ms60ms3rd
Unattributable169ms4ms0ms3rd
https://cpwebassets.codepen.io/assets/packs/js/everypage-4eb662cbcfa735a99fa7.js151ms149ms2ms3rd
https://codepen.io/cdn-cgi/challenge-platform/scripts/jsd/main.js84ms81ms1ms3rd
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
8 fonts (167 KB)
PASS
8 fonts (167 KB)
Info::
8 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

8

167 KB total

Render-blocking

0

of 8

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s 1.5 s 2.0 s FCP 1.8 s LCP 2.0 shttps://codepen.io/cf-fonts/s/lato/5.0.18/latin/400/normal.woff2normal.woff2 https://codepen.io/cf-fonts/s/lato/5.0.18/latin/400/normal.woff2 — 23.3 KiB — 0 ms — font-display: swaphttps://codepen.io/cf-fonts/s/lato/5.0.18/latin/900/normal.woff2normal.woff2 https://codepen.io/cf-fonts/s/lato/5.0.18/latin/900/normal.woff2 — 22.2 KiB — 0 ms — font-display: swaphttps://public.codepenassets.com/fonts/telefon-black.654a55c7fc5c69899e4c776e9440cb.woff2telefon-black.654a55c7f... https://public.codepenassets.com/fonts/telefon-black.654a55c7fc5c69899e4c776e9440cb.woff2 — 36.0 KiB — 0 ms — font-display: swaphttps://codepen.io/cf-fonts/s/lato/5.0.18/latin/700/normal.woff2normal.woff2 https://codepen.io/cf-fonts/s/lato/5.0.18/latin/700/normal.woff2 — 22.7 KiB — 0 ms — font-display: swaphttps://public.codepenassets.com/fonts/telefon-bold.30e9132f184f36be19ce6e4b9024ab.woff2telefon-bold.30e9132f18... https://public.codepenassets.com/fonts/telefon-bold.30e9132f184f36be19ce6e4b9024ab.woff2 — 37.1 KiB — 0 ms — font-display: swaphttps://codepen.io/cf-fonts/s/lato/5.0.18/latin/400/italic.woff2italic.woff2 https://codepen.io/cf-fonts/s/lato/5.0.18/latin/400/italic.woff2 — 24.1 KiB — 0 ms — font-display: swapdata:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAAUsAAsAAAAACJwAAQAAAAAAAAAAAAAAAAAAAAA…font-woff;charset=utf-8... data:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAAUsAAsAAAAACJwAAQAAAAAAAAAAAAAAAAAAAAA… — 1.3 KiB — 0 ms — font-display: swapdata:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAAUsAAsAAAAACJwAAQAAAAAAAAAAAAAAAAAAAAA…font-woff;charset=utf-8... data:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAAUsAAsAAAAACJwAAQAAAAAAAAAAAAAAAAAAAAA… — 0 B — 0 ms — font-display: swap
normal.woff2 woff2 swap
Size 23 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
normal.woff2 woff2 swap
Size 22 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
telefon-black.654a55c7f... woff2 swap
Size 36 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
normal.woff2 woff2 swap
Size 23 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
telefon-bold.30e9132f18... woff2 swap
Size 37 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
italic.woff2 woff2 swap
Size 24 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
font-woff;charset=utf-8... woff swap
Size 1 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-woff;charset=utf-8... woff swap
Size 0 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)
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
94 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
100% of JavaScript execution is third-party
First-party Third-party 1297ms · 690KB · €14/mo
codepen.io
Other
Costly
Execution 497ms
Transfer 7 KB
Monthly Cost €5/mo
cpwebassets.codepen.io
Other
Costly
Execution 396ms
Transfer 660 KB
Unused 64%
Monthly Cost €4/mo
Unattributable
Other
Optional
Execution 169ms
Transfer 0 KB
Monthly Cost €2/mo
cpwebassets.codepen.io
Other
Optional
Execution 151ms
Transfer 22 KB
Monthly Cost €2/mo
codepen.io
Other
Optional
Execution 84ms
Transfer 0 KB
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • codepen.io adds 497ms and costs ~€5/month
  • cpwebassets.codepen.io adds 396ms and costs ~€4/month

100% 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

codepen.io 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

cpwebassets.codepen.io takes 396ms 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

64% of cpwebassets.codepen.io'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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