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Performance

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

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

Mobile Desktop
31
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
87
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
73
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.

4.17 s

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

13.64 s

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

2.77 s

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.

7.10 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.

13.77 s

Page Load Progression

381 ms
762 ms
1.1 s
1.5 s
1.9 s
2.3 s
2.7 s
3.0 s
Checks
14
6 PASS 4 REVIEW 2 FIX
F
JS Execution Cost
Action
7935ms total JS execution
FIX
7935ms total JS execution
Warning::
https://stackoverflow.com/questions: 1157ms CPU time
Warning::
Unattributable: 974ms CPU time
Warning::
https://cdn.cookielaw.org/scripttemplates/202601.2...: 936ms CPU time
Warning::
https://stackoverflow.com/Content/Js/islands/homep...: 614ms CPU time
Warning::
https://www.googletagmanager.com/gtag/js?id=G-WCZ0...: 468ms CPU time
Warning::
Third-party scripts: 4382ms (55% of total)

Main Thread Breakdown

Script Evaluation 56% Style & Layout 13% Other 13% Script Parsing & Compilation 10% Parse HTML & CSS 4%
ScriptTotalScriptingParse/CompileParty
https://stackoverflow.com/questions1157ms106ms28ms1st
Unattributable974ms19ms0ms3rd
https://cdn.cookielaw.org/scripttemplates/202601.2.0/otGPP.js936ms825ms37ms3rd
https://stackoverflow.com/Content/Js/islands/homepage-wizard.en.js?v=a74b3480697c614ms483ms8ms1st
https://www.googletagmanager.com/gtag/js?id=G-WCZ03SZFCQ468ms383ms81ms3rd
https://s.lngtdv.com/stackoverflow/default.1775148653.js449ms370ms59ms3rd
https://stackoverflow.com/cdn-cgi/challenge-platform/scripts/jsd/main.js447ms415ms5ms1st
https://pagead2.googlesyndication.com/pagead/managed/js/gpt/m202604010101/pubads_impl.js?cb=31097585396ms293ms96ms3rd
https://stackoverflow.com/Content/Js/stub.en.js?v=e307fb81e738328ms191ms8ms1st
https://cdn.cookielaw.org/scripttemplates/202601.2.0/otBannerSdk.js318ms140ms101ms3rd

Showing top 10 of 24 scripts

F
JS Bundles
Action
39 scripts, 647 KB unused
FIX
39 scripts, 647 KB unused
Warning::
https://s.lngtdv.com/prebid/stackoverflow/prebid10...: 141 KB unused (82%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://pagead2.googlesyndication.com/pagead/manag...: 138 KB unused (75%)
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.
Info::
Total unused JavaScript: 647 KB
647 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://s.lngtdv.com/prebid/stackoverflow/prebid10.27.0.1774971607.min.js172 KB141 KB (82%)✓3rd
https://pagead2.googlesyndication.com/pagead/managed/js/gpt/m202604010101/pubads_impl.js?cb=31097585182 KB138 KB (75%)✓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://www.googletagmanager.com/gtag/js?id=G-WCZ03SZFCQ153 KB59 KB (39%)✓3rd
https://s.lngtdv.com/stackoverflow/default.1775148653.js71 KB41 KB (58%)✓3rd
https://stackoverflow.com/Content/Js/webpack-chunks/svelte.en.js?v=f773033c4e0b32 KB32 KB (99%)✓1st
https://stackoverflow.com/px.js?ch=10 KB—✓1st
https://stackoverflow.com/Content/Js/webpack-chunks/620.en.js?v=a432091814d82 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
1.9 MB transferred, 79 requests
REVIEW
1.9 MB transferred, 79 requests
Info::
Page weighs 6.6 MB (1.9 MB transferred)
Warning::
JavaScript is 1.2 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.2 MB
Info::
79 HTTP requests
Info::
Estimated 0.41 g CO2 per page load
1.9 MB / 2.4 MB budget
1.9 MB transferred
79 requests
0.41 g CO2 per page load
JavaScript 1.2 MiB 63%
Images 299.0 KiB 15%
CSS 189.8 KiB 10%
Other 156.4 KiB 8%
HTML 47.6 KiB 2%
Other 25.3 KiB 1%
Other 5.2 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
57% third-party, 0 ms blocking
REVIEW
57% third-party, 0 ms blocking
Warning::
Third-party code accounts for 57% of page weight (1.1 MiB of 1.9 MiB)
Info::
Third-party blocking time is low (0 ms)
43%
57%
First-party Third-party
B
Image Optimization
21 images, 0 KB saveable
REVIEW
21 images, 0 KB saveable
Info::
All images are well-optimized
21 images 299 KB
0 oversized -0 KB
21 legacy format
0 missing dimensions CLS risk
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
55% of JavaScript execution is third-party
First-party Third-party 4382ms · 899KB · $58/mo
Unattributable
Other
Costly
Execution 974ms
Transfer 0 KB
Monthly Cost $13/mo
OneTrust
Consent
Essential
Execution 936ms
Transfer 22 KB
Monthly Cost $12/mo
Google Tag Manager
Tag Manager
Costly
Execution 468ms
Transfer 153 KB
Unused 39%
Monthly Cost $6/mo
s.lngtdv.com
Other
Costly
Execution 449ms
Transfer 71 KB
Unused 58%
Monthly Cost $6/mo
pagead2.googlesyndication.com
Other
Costly
Execution 396ms
Transfer 182 KB
Unused 75%
Monthly Cost $5/mo
OneTrust
Consent
Essential
Execution 318ms
Transfer 128 KB
Unused 56%
Monthly Cost $4/mo
s.lngtdv.com
Other
Costly
Execution 308ms
Transfer 172 KB
Unused 82%
Monthly Cost $4/mo
pagead2.googlesyndication.com
Other
Optional
Execution 138ms
Transfer 34 KB
Monthly Cost $2/mo
ajax.googleapis.com
Other
Optional
Execution 129ms
Transfer 30 KB
Monthly Cost $2/mo
OneTrust
Consent
Essential
Execution 109ms
Transfer 9 KB
Monthly Cost $1/mo
accounts.google.com
Other
Optional
Execution 88ms
Transfer 93 KB
Unused 75%
Monthly Cost $1/mo
OneTrust
Consent
Essential
Execution 69ms
Transfer 2 KB
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • Unattributable adds 974ms and costs ~$13/month
  • Google Tag Manager adds 468ms and costs ~$6/month
  • s.lngtdv.com adds 449ms and costs ~$6/month
  • pagead2.googlesyndication.com adds 396ms and costs ~$5/month
  • s.lngtdv.com adds 308ms and costs ~$4/month

55% 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 974ms 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

Google Tag Manager takes 468ms 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

s.lngtdv.com takes 449ms 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

58% 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

pagead2.googlesyndication.com 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

75% 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

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

s.lngtdv.com takes 308ms 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

82% 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

75% of accounts.google.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

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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