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https://smashingmagazine.com

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
87
GRADE
B
FIX
2
REVIEW
4
PASS
9
INFO
2

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

Mobile Desktop
67
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.
100
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.

2.65 s

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

5.24 s

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

318 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.

4.46 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.

5.29 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
9 PASS 4 REVIEW 2 FIX
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 (435.9 KiB of 436.0 KiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
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
23 images, 0 KB saveable
REVIEW
23 images, 0 KB saveable
Warning::
https://www.smashingmagazine.com/images/logo.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.smashingmagazine.com/images/smashing-c... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
23 images 66 KB
0 oversized -0 KB
12 legacy format
2 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

C
JS Execution Cost
Action
1769ms total JS execution
REVIEW
1769ms total JS execution
Warning::
https://www.smashingmagazine.com/: 1059ms CPU time
Warning::
Unattributable: 411ms CPU time
Warning::
https://www.googletagmanager.com/gtag/js?id=G-CXX3...: 299ms CPU time
Warning::
Third-party scripts: 1769ms (100% of total)

Main Thread Breakdown

Style & Layout 43% Other 25% Script Evaluation 16% Script Parsing & Compilation 7% Parse HTML & CSS 6% Rendering 3%
ScriptTotalScriptingParse/CompileParty
https://www.smashingmagazine.com/1059ms61ms37ms3rd
Unattributable411ms16ms0ms3rd
https://www.googletagmanager.com/gtag/js?id=G-CXX395KXNG299ms196ms89ms3rd
B
JS Bundles
3 scripts, 84 KB unused
REVIEW
3 scripts, 84 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-CXX3...: 84 KB unused (56%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 84 KB
84 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-CXX395KXNG150 KB84 KB (56%)✓3rd
https://www.smashingmagazine.com/js/nav-v2.js1 KB—✓3rd
https://www.smashingmagazine.com/.netlify/scripts/rum4 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

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
436 KB transferred, 41 requests
PASS
436 KB transferred, 41 requests
Info::
Page weighs 1.3 MB (436 KB transferred)
Info::
41 HTTP requests
Info::
Estimated 0.09 g CO2 per page load
436 KB / 2.4 MB budget
436 KB transferred
41 requests
0.09 g CO2 per page load
JavaScript 154.9 KiB 36%
HTML 75.2 KiB 17%
CSS 72.1 KiB 17%
Images 66.3 KiB 15%
Fonts 64.9 KiB 15%
Other 2.2 KiB 1%
Other 366 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+
Font Loading
4 fonts (65 KB)
PASS
4 fonts (65 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

4

65 KB total

Render-blocking

0

of 4

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s FCP 2.7 s LCP 5.2 shttps://www.smashingmagazine.com/fonts/ElenaWebRegular/ElenaWebRegular-subset-v2.woff2ElenaWebRegular-subset-... https://www.smashingmagazine.com/fonts/ElenaWebRegular/ElenaWebRegular-subset-v2.woff2 — 16.6 KiB — 31 ms — font-display: swaphttps://www.smashingmagazine.com/fonts/ElenaWebBold/ElenaWebBold-subset-v2.woff2ElenaWebBold-subset-v2.... https://www.smashingmagazine.com/fonts/ElenaWebBold/ElenaWebBold-subset-v2.woff2 — 17.0 KiB — 30 ms — font-display: swaphttps://www.smashingmagazine.com/fonts/MijaBold/Mija_Bold-webfont-subset-v2.woff2Mija_Bold-webfont-subse... https://www.smashingmagazine.com/fonts/MijaBold/Mija_Bold-webfont-subset-v2.woff2 — 14.2 KiB — 31 ms — font-display: swaphttps://www.smashingmagazine.com/fonts/ElenaWebRegularItalic/ElenaWebRegularItalic-subset-v2.woff2ElenaWebRegularItalic-s... https://www.smashingmagazine.com/fonts/ElenaWebRegularItalic/ElenaWebRegularItalic-subset-v2.woff2 — 17.1 KiB — 31 ms — font-display: swap
ElenaWebRegular-subset-... woff2 swap
Size 17 KB
Load time 31 ms
Start 101 ms
Risk FOUT — text flashes from fallback to web font
ElenaWebBold-subset-v2.... woff2 swap
Size 17 KB
Load time 30 ms
Start 102 ms
Risk FOUT — text flashes from fallback to web font
Mija_Bold-webfont-subse... woff2 swap
Size 14 KB
Load time 31 ms
Start 102 ms
Risk FOUT — text flashes from fallback to web font
ElenaWebRegularItalic-s... woff2 swap
Size 17 KB
Load time 31 ms
Start 102 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+
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
9 hints, 0 missing preconnects
PASS
9 hints, 0 missing preconnects
Info::
Page uses 9 resource hint(s)

Current Resource Hints

preconnect
5
preload
4
dns-prefetch
—
prefetch
—

9 resource hints configured

A
Page Weight Inventory
41 resources · 436 KB · 84 KB savings available
PASS
41 resources · 436 KB · 84 KB savings available
Info::
Within 1MB page-weight target
Got: 436 KB
Info::
~84 KB of savings available
Warning::
40 third-party resources (100% of weight)
41 resources · 436.0 KiB · 40 third-party Within 1MB page-weight target
JavaScript 36% · 154.9 KiB
Document 17% · 75.2 KiB
CSS 17% · 72.1 KiB
Image 16% · 68.4 KiB
Font 15% · 64.9 KiB
Other 0% · 534 B

~84.3 KiB of savings available

Remove unused JavaScript: 84.3 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
Network Waterfall
41 requests over 612ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s FCP 2.7 s LCP 5.2 shttps://smashingmagazine.com// https://smashingmagazine.com/ — 301 — 168 B — 34 ms — h2https://www.smashingmagazine.com/www.smashingmagazine.com/ https://www.smashingmagazine.com/ — 200 — 75.2 KiB — 42 ms — h2https://www.smashingmagazine.com/js/nav-v2.jswww.smashingmagazine.com/js/nav-v2.... https://www.smashingmagazine.com/js/nav-v2.js — 200 — 770 B — 18 ms — h2https://www.smashingmagazine.com/images/logo.svgwww.smashingmagazine.com/images/log... https://www.smashingmagazine.com/images/logo.svg — 200 — 1.2 KiB — 15 ms — h2https://www.smashingmagazine.com/images/smashing-cat/cat-in-the-chair.svgwww.smashingmagazine.com/images/sma... https://www.smashingmagazine.com/images/smashing-cat/cat-in-the-chair.svg — 200 — 7.9 KiB — 167 ms — h2https://www.smashingmagazine.com/fonts/ElenaWebRegular/ElenaWebRegular-subset-v2.woff2www.smashingmagazine.com/fonts/Elen... https://www.smashingmagazine.com/fonts/ElenaWebRegular/ElenaWebRegular-subset-v2.woff2 — 200 — 16.6 KiB — 31 ms — h2https://www.smashingmagazine.com/fonts/ElenaWebBold/ElenaWebBold-subset-v2.woff2www.smashingmagazine.com/fonts/Elen... https://www.smashingmagazine.com/fonts/ElenaWebBold/ElenaWebBold-subset-v2.woff2 — 200 — 17.0 KiB — 30 ms — h2https://www.smashingmagazine.com/fonts/MijaBold/Mija_Bold-webfont-subset-v2.woff2www.smashingmagazine.com/fonts/Mija... https://www.smashingmagazine.com/fonts/MijaBold/Mija_Bold-webfont-subset-v2.woff2 — 200 — 14.2 KiB — 31 ms — h2https://www.smashingmagazine.com/fonts/ElenaWebRegularItalic/ElenaWebRegularItalic-subset-v2.woff2www.smashingmagazine.com/fonts/Elen... https://www.smashingmagazine.com/fonts/ElenaWebRegularItalic/ElenaWebRegularItalic-subset-v2.woff2 — 200 — 17.1 KiB — 31 ms — h2https://www.smashingmagazine.com/css/main.csswww.smashingmagazine.com/css/main.c... https://www.smashingmagazine.com/css/main.css — 200 — 67.8 KiB — 154 ms — h2data:image/avif;base64,AAAAIGZ0eXBhdmlmAAAAAGF2aWZtaWYxbWlhZk1BMUIAAADybWV0YQAAAAAAAAAoaGRscgAAAAAA…data:image/avif;base64,AAAAIGZ0eXBh... data:image/avif;base64,AAAAIGZ0eXBhdmlmAAAAAGF2aWZtaWYxbWlhZk1BMUIAAADybWV0YQAAAAAAAAAoaGRscgAAAAAA… — 200 — 0 B — 0 ms — datadata:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAPNtZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw…data:image/avif;base64,AAAAHGZ0eXBt... data:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAPNtZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw… — 200 — 0 B — 0 ms — datadata:image/avif;base64,AAAAIGZ0eXBhdmlmAAAAAGF2aWZtaWYxbWlhZk1BMUIAAAGhbWV0YQAAAAAAAAAoaGRscgAAAAAA…data:image/avif;base64,AAAAIGZ0eXBh... data:image/avif;base64,AAAAIGZ0eXBhdmlmAAAAAGF2aWZtaWYxbWlhZk1BMUIAAAGhbWV0YQAAAAAAAAAoaGRscgAAAAAA… — 200 — 0 B — 0 ms — datadata:image/avif;base64,AAAAGGZ0eXBhdmlmAAAAAGF2aWZtaWYxAAAA2W1ldGEAAAAAAAAAIWhkbHIAAAAAAAAAAHBpY3QA…data:image/avif;base64,AAAAGGZ0eXBh... data:image/avif;base64,AAAAGGZ0eXBhdmlmAAAAAGF2aWZtaWYxAAAA2W1ldGEAAAAAAAAAIWhkbHIAAAAAAAAAAHBpY3QA… — 200 — 0 B — 0 ms — datadata:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAO5tZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw…data:image/avif;base64,AAAAHGZ0eXBt... data:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAO5tZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw… — 200 — 0 B — 0 ms — datadata:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAPNtZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw…data:image/avif;base64,AAAAHGZ0eXBt... data:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAPNtZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw… — 200 — 0 B — 0 ms — datadata:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAPNtZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw…data:image/avif;base64,AAAAHGZ0eXBt... data:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAPNtZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw… — 200 — 0 B — 0 ms — datadata:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAPNtZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw…data:image/avif;base64,AAAAHGZ0eXBt... data:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAPNtZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw… — 200 — 0 B — 0 ms — datadata:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAPNtZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw…data:image/avif;base64,AAAAHGZ0eXBt... data:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAPNtZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw… — 200 — 0 B — 0 ms — datahttps://files.smashing.media/person-of-the-week/yiying-lu-250px.aviffiles.smashing.media/person-of-the-... https://files.smashing.media/person-of-the-week/yiying-lu-250px.avif — 200 — 4.9 KiB — 123 ms — h2https://files.smashing.media/community-links/juergen-zimmermann-100px-opt.pngfiles.smashing.media/community-link... https://files.smashing.media/community-links/juergen-zimmermann-100px-opt.png — 200 — 7.8 KiB — 126 ms — h2https://files.smashing.media/community-links/ian-lloyd-100px-opt.pngfiles.smashing.media/community-link... https://files.smashing.media/community-links/ian-lloyd-100px-opt.png — 200 — 7.3 KiB — 128 ms — h2https://files.smashing.media/community-links/taras-bakusevych-opt.pngfiles.smashing.media/community-link... https://files.smashing.media/community-links/taras-bakusevych-opt.png — 200 — 6.6 KiB — 123 ms — h2https://files.smashing.media/community-links/stephanie-walter-100px-opt.pngfiles.smashing.media/community-link... https://files.smashing.media/community-links/stephanie-walter-100px-opt.png — 200 — 8.5 KiB — 133 ms — h2https://files.smashing.media/community-links/tey-bannerman-100px-opt.pngfiles.smashing.media/community-link... https://files.smashing.media/community-links/tey-bannerman-100px-opt.png — 200 — 8.0 KiB — 130 ms — h2https://files.smashing.media/community-links/steve-frenzel-100px-opt.pngfiles.smashing.media/community-link... https://files.smashing.media/community-links/steve-frenzel-100px-opt.png — 200 — 8.8 KiB — 128 ms — h2https://www.smashingmagazine.com/manifest.jsonwww.smashingmagazine.com/manifest.j... https://www.smashingmagazine.com/manifest.json — 200 — 366 B — 291 ms — h2https://www.smashingmagazine.com/css/print.csswww.smashingmagazine.com/css/print.... https://www.smashingmagazine.com/css/print.css — 200 — 4.3 KiB — 157 ms — h2https://www.googletagmanager.com/gtag/js?id=G-CXX395KXNGwww.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-CXX395KXNG — 200 — 150.0 KiB — 45 ms — h2https://www.smashingmagazine.com/.netlify/scripts/rumwww.smashingmagazine.com/.netlify/s... https://www.smashingmagazine.com/.netlify/scripts/rum — 200 — 4.2 KiB — 14 ms — h2
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s FCP 2.7 s LCP 5.2 shttps://smashingmagazine.com// https://smashingmagazine.com/ — 301 — 168 B — 34 ms — h2https://www.smashingmagazine.com/www.smashingmagazine.com/ https://www.smashingmagazine.com/ — 200 — 75.2 KiB — 42 ms — h2https://www.smashingmagazine.com/js/nav-v2.jswww.smashingmagazine.com/js/nav-v2.... https://www.smashingmagazine.com/js/nav-v2.js — 200 — 770 B — 18 ms — h2https://www.smashingmagazine.com/images/logo.svgwww.smashingmagazine.com/images/log... https://www.smashingmagazine.com/images/logo.svg — 200 — 1.2 KiB — 15 ms — h2https://www.smashingmagazine.com/images/smashing-cat/cat-in-the-chair.svgwww.smashingmagazine.com/images/sma... https://www.smashingmagazine.com/images/smashing-cat/cat-in-the-chair.svg — 200 — 7.9 KiB — 167 ms — h2https://www.smashingmagazine.com/fonts/ElenaWebRegular/ElenaWebRegular-subset-v2.woff2www.smashingmagazine.com/fonts/Elen... https://www.smashingmagazine.com/fonts/ElenaWebRegular/ElenaWebRegular-subset-v2.woff2 — 200 — 16.6 KiB — 31 ms — h2https://www.smashingmagazine.com/fonts/ElenaWebBold/ElenaWebBold-subset-v2.woff2www.smashingmagazine.com/fonts/Elen... https://www.smashingmagazine.com/fonts/ElenaWebBold/ElenaWebBold-subset-v2.woff2 — 200 — 17.0 KiB — 30 ms — h2https://www.smashingmagazine.com/fonts/MijaBold/Mija_Bold-webfont-subset-v2.woff2www.smashingmagazine.com/fonts/Mija... https://www.smashingmagazine.com/fonts/MijaBold/Mija_Bold-webfont-subset-v2.woff2 — 200 — 14.2 KiB — 31 ms — h2https://www.smashingmagazine.com/fonts/ElenaWebRegularItalic/ElenaWebRegularItalic-subset-v2.woff2www.smashingmagazine.com/fonts/Elen... https://www.smashingmagazine.com/fonts/ElenaWebRegularItalic/ElenaWebRegularItalic-subset-v2.woff2 — 200 — 17.1 KiB — 31 ms — h2https://www.smashingmagazine.com/css/main.csswww.smashingmagazine.com/css/main.c... https://www.smashingmagazine.com/css/main.css — 200 — 67.8 KiB — 154 ms — h2data:image/avif;base64,AAAAIGZ0eXBhdmlmAAAAAGF2aWZtaWYxbWlhZk1BMUIAAADybWV0YQAAAAAAAAAoaGRscgAAAAAA…data:image/avif;base64,AAAAIGZ0eXBh... data:image/avif;base64,AAAAIGZ0eXBhdmlmAAAAAGF2aWZtaWYxbWlhZk1BMUIAAADybWV0YQAAAAAAAAAoaGRscgAAAAAA… — 200 — 0 B — 0 ms — datadata:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAPNtZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw…data:image/avif;base64,AAAAHGZ0eXBt... data:image/avif;base64,AAAAHGZ0eXBtaWYxAAAAAG1pZjFhdmlmbWlhZgAAAPNtZXRhAAAAAAAAACFoZGxyAAAAAAAAAABw… — 200 — 0 B — 0 ms — datadata:image/avif;base64,AAAAIGZ0eXBhdmlmAAAAAGF2aWZtaWYxbWlhZk1BMUIAAAGhbWV0YQAAAAAAAAAoaGRscgAAAAAA…data:image/avif;base64,AAAAIGZ0eXBh... data:image/avif;base64,AAAAIGZ0eXBhdmlmAAAAAGF2aWZtaWYxbWlhZk1BMUIAAAGhbWV0YQAAAAAAAAAoaGRscgAAAAAA… — 200 — 0 B — 0 ms — datadata:image/avif;base64,AAAAGGZ0eXBhdmlmAAAAAGF2aWZtaWYxAAAA2W1ldGEAAAAAAAAAIWhkbHIAAAAAAAAAAHBpY3QA…data:image/avif;base64,AAAAGGZ0eXBh... 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HTML JavaScript CSS Images Fonts XHR/Fetch Other
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 1769ms · 225KB · €19/mo
www.smashingmagazine.com
Other
Costly
Execution 1059ms
Transfer 75 KB
Monthly Cost €12/mo
Unattributable
Other
Costly
Execution 411ms
Transfer 0 KB
Monthly Cost €4/mo
Google Tag Manager
Tag Manager
Costly
Execution 299ms
Transfer 150 KB
Unused 56%
Monthly Cost €3/mo

These scripts may cost more than they're worth

  • www.smashingmagazine.com adds 1059ms and costs ~€12/month
  • Unattributable adds 411ms and costs ~€4/month
  • Google Tag Manager adds 299ms and costs ~€3/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

www.smashingmagazine.com takes 1059ms 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

Unattributable takes 411ms 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 299ms 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

56% of Google Tag Manager'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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