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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
74
GRADE
C
FIX
1
REVIEW
5
PASS
6
INFO
2

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

Mobile Desktop
72
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
92
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
77
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
82
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.

712 ms

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

2.61 s

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

286 ms

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

0.001

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

1.56 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.

2.61 s

Page Load Progression

414 ms
829 ms
1.2 s
1.7 s
2.1 s
2.5 s
2.9 s
3.3 s
Checks
14
6 PASS 5 REVIEW 1 FIX
D
JS Bundles
Action
38 scripts, 467 KB unused
FIX
38 scripts, 467 KB unused
Warning::
https://pagead2.googlesyndication.com/pagead/manag...: 136 KB unused (74%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://stackoverflow.com/Content/Js/full-anon.en....: 95 KB unused (74%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.cookielaw.org/scripttemplates/202601.2...: 72 KB unused (56%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://accounts.google.com/gsi/client: 70 KB unused (75%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://s.lngtdv.com/stackoverflow/default.1775148...: 43 KB unused (60%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 467 KB
467 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://pagead2.googlesyndication.com/pagead/managed/js/gpt/m202603310101/pubads_impl.js?cb=31097584182 KB136 KB (74%)✓3rd
https://stackoverflow.com/Content/Js/full-anon.en.js?v=037e97b07fca129 KB95 KB (74%)✓1st
https://cdn.cookielaw.org/scripttemplates/202601.2.0/otBannerSdk.js128 KB72 KB (56%)✓3rd
https://accounts.google.com/gsi/client93 KB70 KB (75%)✓3rd
https://s.lngtdv.com/stackoverflow/default.1775148653.js71 KB43 KB (60%)✓3rd
https://stackoverflow.com/Content/Js/webpack-chunks/svelte.en.js?v=f773033c4e0b32 KB32 KB (99%)✓1st
https://stackoverflow.com/Content/Js/third-party/npm/@stackoverflow/stacks/dist/js/stacks.min.js?v=c7bcc7a1b4fd30 KB21 KB (68%)✓1st
https://stackoverflow.com/Content/Js/webpack-chunks/stacks-svelte-labs.en.js?v=b9cf031e2bdd8 KB—✓1st
https://stackoverflow.com/Content/Js/webpack-chunks/2458.en.js?v=33cc3da05f781 KB—✓1st
https://stackoverflow.com/px.js?ch=11 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
Page Weight Budget
Action
1.6 MB transferred, 79 requests
REVIEW
1.6 MB transferred, 79 requests
Info::
Page weighs 6.0 MB (1.6 MB transferred)
Warning::
JavaScript is 1.1 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.1 MB
Info::
79 HTTP requests
Info::
Estimated 0.33 g CO2 per page load
1.6 MB / 2.4 MB budget
1.6 MB transferred
79 requests
0.33 g CO2 per page load
JavaScript 1.1 MiB 67%
CSS 189.9 KiB 12%
Other 156.4 KiB 10%
Images 112.6 KiB 7%
HTML 47.5 KiB 3%
Other 25.3 KiB 2%
Other 5.5 KiB 0%
0 2.4 MB 4.9 MB
Approaching limit

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

B
Third-Party Impact
59% third-party, 0 ms blocking
REVIEW
59% third-party, 0 ms blocking
Warning::
Third-party code accounts for 59% of page weight (948.9 KiB of 1.6 MiB)
Info::
Third-party blocking time is low (0 ms)
41%
59%
First-party Third-party
B
Image Optimization
22 images, 0 KB saveable
REVIEW
22 images, 0 KB saveable
Info::
All images are well-optimized
22 images 113 KB
0 oversized -0 KB
21 legacy format
0 missing dimensions CLS risk
C
JS Execution Cost
Action
1684ms total JS execution
REVIEW
1684ms total JS execution
Warning::
https://stackoverflow.com/questions: 358ms CPU time
Warning::
https://cdn.cookielaw.org/scripttemplates/202601.2...: 252ms CPU time
Info::
Unattributable: 204ms CPU time
Info::
https://stackoverflow.com/Content/Js/islands/homep...: 143ms CPU time
Info::
https://pagead2.googlesyndication.com/pagead/manag...: 129ms CPU time
Warning::
Third-party scripts: 879ms (52% of total)

Main Thread Breakdown

Script Evaluation 56% Style & Layout 14% Other 13% Script Parsing & Compilation 9% Parse HTML & CSS 4%
ScriptTotalScriptingParse/CompileParty
https://stackoverflow.com/questions358ms27ms6ms1st
https://cdn.cookielaw.org/scripttemplates/202601.2.0/otGPP.js252ms215ms10ms3rd
Unattributable204ms6ms0ms3rd
https://stackoverflow.com/Content/Js/islands/homepage-wizard.en.js?v=a74b3480697c143ms115ms2ms1st
https://pagead2.googlesyndication.com/pagead/managed/js/gpt/m202603310101/pubads_impl.js?cb=31097584129ms98ms24ms3rd
https://www.googletagmanager.com/gtag/js?id=G-WCZ03SZFCQ121ms92ms21ms3rd
https://stackoverflow.com/cdn-cgi/challenge-platform/scripts/jsd/main.js103ms99ms1ms1st
https://s.lngtdv.com/stackoverflow/default.1775148653.js88ms71ms12ms3rd
https://cdn.cookielaw.org/scripttemplates/202601.2.0/otBannerSdk.js86ms38ms21ms3rd
https://stackoverflow.com/Content/Js/stub.en.js?v=e307fb81e73885ms52ms3ms1st

Showing top 10 of 12 scripts

B
HTTP Caching
private
REVIEW
private
Info::
Cache-Control header is set
Got: private
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

private

DirectiveValueMeaning
private—Only browser cache, not CDN/proxy
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
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+
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
79 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
52% of JavaScript execution is third-party
First-party Third-party 879ms · 558KB · $12/mo
OneTrust
Consent
Essential
Execution 252ms
Transfer 22 KB
Monthly Cost $3/mo
Unattributable
Other
Costly
Execution 204ms
Transfer 0 KB
Monthly Cost $3/mo
pagead2.googlesyndication.com
Other
Optional
Execution 129ms
Transfer 182 KB
Unused 74%
Monthly Cost $2/mo
Google Tag Manager
Tag Manager
Optional
Execution 121ms
Transfer 153 KB
Monthly Cost $2/mo
s.lngtdv.com
Other
Optional
Execution 88ms
Transfer 71 KB
Unused 60%
Monthly Cost $1/mo
OneTrust
Consent
Essential
Execution 86ms
Transfer 128 KB
Unused 56%
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • Unattributable adds 204ms and costs ~$3/month

52% 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 204ms 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

74% of pagead2.googlesyndication.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

60% of s.lngtdv.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

56% of OneTrust'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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