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Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
96
GRADE
A
FIX
0
REVIEW
1
PASS
14
INFO
2

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

Mobile Desktop
98
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
93
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
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.

1.70 s

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

1.84 s

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

0 ms

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

0.071

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

1.70 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.

1.84 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
17
14 PASS 1 REVIEW
B
Third-Party Impact
49% third-party, 0 ms blocking
REVIEW
49% third-party, 0 ms blocking
Info::
Third-party code accounts for 49% of page weight (37.0 KiB of 75.9 KiB)
Info::
Third-party blocking time is low (0 ms)
51%
49%
First-party Third-party
A+
Page Weight Budget
76 KB transferred, 15 requests
PASS
76 KB transferred, 15 requests
Info::
Page weighs 133 KB (76 KB transferred)
Info::
15 HTTP requests
Info::
Estimated 0.02 g CO2 per page load
76 KB / 2.4 MB budget
76 KB transferred
15 requests
0.02 g CO2 per page load
Fonts 30.1 KiB 40%
JavaScript 21.3 KiB 28%
Images 15.1 KiB 20%
HTML 6.3 KiB 8%
Other 1.7 KiB 2%
Other 759 B 1%
Other 648 B 1%
Other 0 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
1 images, 0 KB saveable
PASS
1 images, 0 KB saveable
Info::
All images are well-optimized
1 images 15 KB
0 oversized -0 KB
1 legacy format
0 missing dimensions CLS risk
A+
JS Execution Cost
366ms total JS execution
PASS
366ms total JS execution
Info::
Unattributable: 135ms CPU time
Info::
https://m.servedby-buysellads.com/monetization.cus...: 121ms CPU time
Info::
https://js.org/: 110ms CPU time
Warning::
Third-party scripts: 256ms (70% of total)

Main Thread Breakdown

Style & Layout 39% Other 36% Script Evaluation 17% Rendering 4%
ScriptTotalScriptingParse/CompileParty
Unattributable135ms9ms0ms3rd
https://m.servedby-buysellads.com/monetization.custom.js121ms19ms2ms3rd
https://js.org/110ms12ms1ms1st
A+
Font Loading
2 fonts (30 KB)
PASS
2 fonts (30 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

30 KB total

Render-blocking

0

of 2

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 FCP 1.7 s LCP 1.8 shttps://js.org/fnt/source-sans-3-v9-latin-regular.woff2source-sans-3-v9-latin-... https://js.org/fnt/source-sans-3-v9-latin-regular.woff2 — 15.0 KiB — 223 ms — font-display: swaphttps://js.org/fnt/source-sans-3-v9-latin-600.woff2source-sans-3-v9-latin-... https://js.org/fnt/source-sans-3-v9-latin-600.woff2 — 15.0 KiB — 226 ms — font-display: swap
source-sans-3-v9-latin-... woff2 swap
Size 15 KB
Load time 223 ms
Start 269 ms
Risk FOUT — text flashes from fallback to web font
source-sans-3-v9-latin-... woff2 swap
Size 15 KB
Load time 226 ms
Start 269 ms
Risk FOUT — text flashes from fallback to web font
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+
JS Bundles
4 scripts, 0 KB unused
PASS
4 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://js.org/main.js1 KB—✓1st
https://m.servedby-buysellads.com/monetization.custom.js7 KB—✓3rd
https://cdn.carbonads.com/carbon.js?serve=CESD4K3E&placement=jsorg10 KB—✓3rd
https://api.github.com/repos/js-org/js.org?callback=cb_qu75vu8b8y3 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
3 hints, 0 missing preconnects
PASS
3 hints, 0 missing preconnects
Info::
Page uses 3 resource hint(s)

Current Resource Hints

preconnect
—
preload
3
dns-prefetch
—
prefetch
—

3 resource hints configured

A
Page Weight Inventory
15 resources · 76 KB · 0 KB savings available
PASS
15 resources · 76 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 76 KB
Warning::
9 third-party resources (49% of weight)
15 resources · 75.9 KiB · 9 third-party Within 1MB page-weight target
Font 40% · 30.1 KiB
JavaScript 28% · 21.3 KiB
Image 21% · 15.9 KiB
Document 8% · 6.3 KiB
Other 3% · 2.4 KiB
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

A+
HTTP Caching
max-age=600 (10 minutes)
PASS
max-age=600 (10 minutes)
Info::
Cache-Control header is set
Got: max-age=600
Info::
Effective TTL: 10 minutes (max-age=600)
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present
Cache-Control

max-age=600

DirectiveValueMeaning
max-age600Cache for 10 minutes
Effective TTL: 600 seconds
Network Waterfall
15 requests over 964ms
INFO
0 ms 500 ms 1.0 s 1.5 s FCP 1.7 s LCP 1.8 shttps://js.org// https://js.org/ — 200 — 6.3 KiB — 256 ms — h2https://js.org/fnt/source-sans-3-v9-latin-regular.woff2/fnt/source-sans-3-v9-latin-regular... https://js.org/fnt/source-sans-3-v9-latin-regular.woff2 — 200 — 15.0 KiB — 223 ms — h2https://js.org/fnt/source-sans-3-v9-latin-600.woff2/fnt/source-sans-3-v9-latin-600.wof... https://js.org/fnt/source-sans-3-v9-latin-600.woff2 — 200 — 15.0 KiB — 226 ms — h2https://js.org/main.js/main.js https://js.org/main.js — 200 — 1.1 KiB — 32 ms — h2https://m.servedby-buysellads.com/monetization.custom.jsm.servedby-buysellads.com/monetizat... https://m.servedby-buysellads.com/monetization.custom.js — 200 — 7.1 KiB — 42 ms — h2https://cdn.carbonads.com/carbon.js?serve=CESD4K3E&placement=jsorgcdn.carbonads.com/carbon.js?serve=C... https://cdn.carbonads.com/carbon.js?serve=CESD4K3E&placement=jsorg — 200 — 10.1 KiB — 46 ms — h2https://js.org/manifest.webmanifest/manifest.webmanifest https://js.org/manifest.webmanifest — 200 — 648 B — 158 ms — h2https://api.github.com/repos/js-org/js.org?callback=cb_qu75vu8b8yapi.github.com/repos/js-org/js.org?... https://api.github.com/repos/js-org/js.org?callback=cb_qu75vu8b8y — 200 — 3.0 KiB — 318 ms — h2https://srv.buysellads.com/ads/CWYDC23J.json?segment=placement:jsorg-badge-bannersrv.buysellads.com/ads/CWYDC23J.jso... https://srv.buysellads.com/ads/CWYDC23J.json?segment=placement:jsorg-badge-banner — 200 — 0 B — 130 ms — h2https://srv.carbonads.net/ads/CESD4K3E.json?segment=placement:jsorgsrv.carbonads.net/ads/CESD4K3E.json... https://srv.carbonads.net/ads/CESD4K3E.json?segment=placement:jsorg — 200 — 0 B — 419 ms — h2https://srv.buysellads.com/ads/CWYDC23J.json?segment=placement:jsorg-badge-bannersrv.buysellads.com/ads/CWYDC23J.jso... https://srv.buysellads.com/ads/CWYDC23J.json?segment=placement:jsorg-badge-banner — 200 — 979 B — 36 ms — h2https://xad.js.org/xad_cxad.js.org/xad_c https://xad.js.org/xad_c — -1 — 0 B — 79 ms — https://js.org/ico/favicon.svg/ico/favicon.svg https://js.org/ico/favicon.svg — 200 — 759 B — 34 ms — h2https://srv.carbonads.net/ads/CESD4K3E.json?segment=placement:jsorgsrv.carbonads.net/ads/CESD4K3E.json... https://srv.carbonads.net/ads/CESD4K3E.json?segment=placement:jsorg — 200 — 781 B — 36 ms — h2https://srv.carbonads.net/static/30242/fa61532e705a1c62ea8f37c4acf9c43fddcf7fc5srv.carbonads.net/static/30242/fa61... https://srv.carbonads.net/static/30242/fa61532e705a1c62ea8f37c4acf9c43fddcf7fc5 — 200 — 15.1 KiB — 109 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
70% of JavaScript execution is third-party
First-party Third-party 256ms · 7KB · €3/mo
Unattributable
Other
Optional
Execution 135ms
Transfer 0 KB
Monthly Cost €1/mo
m.servedby-buysellads.com
Other
Optional
Execution 121ms
Transfer 7 KB
Monthly Cost €1/mo

70% 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

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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