Skip to content
https://www.smashingmagazine.com

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
87
GRADE
B
FIX
0
REVIEW
5
PASS
7
INFO
2

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

Mobile Desktop
100
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.

457 ms

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

668 ms

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

7 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.

502 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

668 ms

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
14
7 PASS 5 REVIEW
B
Third-Party Impact
45% third-party, 0 ms blocking
REVIEW
45% third-party, 0 ms blocking
Info::
Third-party code accounts for 45% of page weight (194.9 KiB of 437.0 KiB)
Info::
Third-party blocking time is low (0 ms)
55%
45%
First-party Third-party
C
Image Optimization
Action
25 images, 0 KB saveable
REVIEW
25 images, 0 KB saveable
Warning::
https://www.smashingmagazine.com/images/smashing-c... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.smashingmagazine.com/images/logo.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
25 images 70 KB
0 oversized -0 KB
14 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

B
JS Bundles
3 scripts, 83 KB unused
REVIEW
3 scripts, 83 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-CXX3...: 83 KB unused (56%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 83 KB
83 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-CXX395KXNG149 KB83 KB (56%)✓3rd
https://www.smashingmagazine.com/js/nav-v2.js1 KB—✓1st
https://www.smashingmagazine.com/.netlify/scripts/rum4 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

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

Green Hosting

No green hosting detected

B
HTTP Caching
No-Cache
REVIEW
No-Cache
Info::
Cache-Control header is set
Got: No-Cache
Info::
ETag present — enables conditional (304) responses
Cache-Control

No-Cache

DirectiveValueMeaning
no-cache—Cache but always revalidate first
A+
Page Weight Budget
437 KB transferred, 43 requests
PASS
437 KB transferred, 43 requests
Info::
Page weighs 1.3 MB (437 KB transferred)
Info::
43 HTTP requests
Info::
Estimated 0.09 g CO2 per page load
437 KB / 2.4 MB budget
437 KB transferred
43 requests
0.09 g CO2 per page load
JavaScript 153.5 KiB 35%
HTML 74.3 KiB 17%
CSS 71.9 KiB 16%
Images 70.1 KiB 16%
Fonts 65.0 KiB 15%
Other 1.9 KiB 0%
Other 371 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+
JS Execution Cost
488ms total JS execution
PASS
488ms total JS execution
Warning::
https://www.smashingmagazine.com/: 352ms CPU time
Info::
Unattributable: 83ms CPU time
Info::
https://www.googletagmanager.com/gtag/js?id=G-CXX3...: 53ms CPU time
Info::
Third-party scripts: 136ms (28% of total)

Main Thread Breakdown

Style & Layout 43% Other 31% Script Evaluation 12% Parse HTML & CSS 5% Rendering 5% Script Parsing & Compilation 5%
ScriptTotalScriptingParse/CompileParty
https://www.smashingmagazine.com/352ms15ms9ms1st
Unattributable83ms3ms0ms3rd
https://www.googletagmanager.com/gtag/js?id=G-CXX395KXNG53ms37ms14ms3rd
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 500 ms 1.0 s FCP 457 ms LCP 668 mshttps://www.smashingmagazine.com/fonts/ElenaWebRegular/ElenaWebRegular-subset-v2.woff2ElenaWebRegular-subset-... https://www.smashingmagazine.com/fonts/ElenaWebRegular/ElenaWebRegular-subset-v2.woff2 — 16.7 KiB — 0 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 — 16.9 KiB — 0 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 — 0 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 — 0 ms — font-display: swap
ElenaWebRegular-subset-... woff2 swap
Size 17 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
ElenaWebBold-subset-v2.... woff2 swap
Size 17 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Mija_Bold-webfont-subse... woff2 swap
Size 14 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
ElenaWebRegularItalic-s... woff2 swap
Size 17 KB
Load time 0 ms
Start 0 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
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
Network Waterfall
43 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
28% of JavaScript execution is third-party
First-party Third-party 136ms · 149KB · €1/mo
Unattributable
Other
Optional
Execution 83ms
Transfer 0 KB
Monthly Cost €1/mo
Google Tag Manager
Tag Manager
Optional
Execution 53ms
Transfer 149 KB
Unused 56%
Monthly Cost €1/mo

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.

Send Feedback