Performance
· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
2.58 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
5.14 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
121 ms
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.
4.86 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.
5.26 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 sDThird-Party ImpactAction89% third-party, 0 ms blockingFIX
CImage OptimizationAction69 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
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.
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.
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.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
CJS Execution CostAction1786ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 586ms | 12ms | 0ms | 3rd |
| https://stackexchange.com/ | 534ms | 70ms | 7ms | 1st |
| https://stackexchange.com/cdn-cgi/challenge-platform/scripts/jsd/main.js | 463ms | 443ms | 5ms | 1st |
| https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js | 131ms | 95ms | 14ms | 3rd |
| https://stackoverflow.com/Content/shared/chrome/chrome.css?v=764504b195d8 | 72ms | 0ms | 0ms | 3rd |
BJS Bundles5 scripts, 20 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js | 30 KB | 20 KB (68%) | ✓ | 3rd |
| https://cdn.sstatic.net/stackexchange/Js/master.js?v=ef8b6ed08310 | 10 KB | — | ✗ | 3rd |
| https://cdn.sstatic.net/stackexchange/Js/universal-login.js?v=30968200101f | 2 KB | — | ✓ | 3rd |
| https://cdn.sstatic.net/stackexchange/Js/topbar.js?v=b2367277c351 | 11 KB | — | ✗ | 3rd |
| https://stackexchange.com/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/main.js? | 12 KB | — | ✓ | 1st |
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
BHTTP CachingprivateREVIEW
private
| Directive | Value | Meaning |
|---|---|---|
| private | — | Only browser cache, not CDN/proxy |
A+Page Weight Budget340 KB transferred, 80 requestsPASS
A+Text CompressionAll text resources are compressedPASS
A+Font LoadingNo web fonts (system fonts)PASS
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
APage Weight Inventory80 resources · 340 KB · 20 KB savings availablePASS
~20.4 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 80 resources | 339.9 KiB | ||||||
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall80 requests over 917msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 586ms | 0 KB | — | $8/mo | Costly |
ajax.googleapis.com ajax.googleapis.com | Other | 131ms | 30 KB | 68% | $2/mo | Optional |
stackoverflow.com stackoverflow.com | Other | 72ms | 99 KB | — | $1/mo | Optional |
These scripts may cost more than they're worth
- Unattributable adds 586ms and costs ~$8/month
44% of JavaScript execution time comes from third-party scripts.
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 586ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
68% of ajax.googleapis.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev