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Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
94
GRADE
A
FIX
1
REVIEW
3
PASS
10
INFO
2

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

Mobile Desktop
83
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
67
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.
83
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.

1.36 s

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

4.66 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.

0.018

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

1.36 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.

4.68 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
16
10 PASS 3 REVIEW 1 FIX
D
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.
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Image Optimization
Action
19 images, 0 KB saveable
REVIEW
19 images, 0 KB saveable
Warning::
https://www.fedoraproject.org/assets/images/digita... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.fedoraproject.org/assets/images/IoT-lo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.fedoraproject.org/assets/images/server... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.fedoraproject.org/assets/images/cloud-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.fedoraproject.org/assets/images/coreos... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.fedoraproject.org/assets/images/logos/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.fedoraproject.org/assets/images/workst... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.fedoraproject.org/assets/images/kde-lo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.fedoraproject.org/assets/images/logo-s... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
19 images 189 KB
0 oversized -0 KB
18 legacy format
9 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

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

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

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

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 Execution Cost
541ms total JS execution
REVIEW
541ms total JS execution
Warning::
https://www.fedoraproject.org/: 299ms CPU time
Info::
Unattributable: 243ms CPU time
Info::
Third-party scripts: 243ms (45% of total)

Main Thread Breakdown

Other 47% Style & Layout 37% Rendering 7% Parse HTML & CSS 6%
ScriptTotalScriptingParse/CompileParty
https://www.fedoraproject.org/299ms8ms2ms1st
Unattributable243ms6ms0ms3rd
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A
Page Weight Budget
844 KB transferred, 33 requests
PASS
844 KB transferred, 33 requests
Info::
Page weighs 1.5 MB (844 KB transferred)
Info::
Fonts are 591 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 591 KB
Info::
33 HTTP requests
Info::
Estimated 0.17 g CO2 per page load
844 KB / 2.4 MB budget
844 KB transferred
33 requests
0.17 g CO2 per page load
Fonts 591.1 KiB 70%
Images 188.6 KiB 22%
CSS 35.3 KiB 4%
HTML 24.9 KiB 3%
Other 3.0 KiB 0%
JavaScript 690 B 0%
0 2.4 MB 4.9 MB
Under budget

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).

Source: web.dev font loading

A+
Third-Party Impact
No third-party resources
PASS
No third-party resources
Info::
No third-party resources detected
No third-party resources detected — all resources are first-party.
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
7 fonts (591 KB)
PASS
7 fonts (591 KB)
Info::
7 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

7

591 KB total

Render-blocking

0

of 7

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 FCP 1.4 s LCP 4.7 shttps://www.fedoraproject.org/fonts/open-sans/OpenSans-Regular.ttfOpenSans-Regular.ttf https://www.fedoraproject.org/fonts/open-sans/OpenSans-Regular.ttf — 77.3 KiB — 0 ms — font-display: swaphttps://www.fedoraproject.org/assets/webfonts/fa-solid-900.woff2fa-solid-900.woff2 https://www.fedoraproject.org/assets/webfonts/fa-solid-900.woff2 — 110.7 KiB — 0 ms — font-display: swaphttps://www.fedoraproject.org/fonts/montserrat/Montserrat-SemiBold.ttfMontserrat-SemiBold.ttf https://www.fedoraproject.org/fonts/montserrat/Montserrat-SemiBold.ttf — 86.3 KiB — 0 ms — font-display: swaphttps://www.fedoraproject.org/fonts/open-sans/OpenSans-Bold.ttfOpenSans-Bold.ttf https://www.fedoraproject.org/fonts/open-sans/OpenSans-Bold.ttf — 75.2 KiB — 0 ms — font-display: swaphttps://www.fedoraproject.org/fonts/montserrat/Montserrat-Bold.ttfMontserrat-Bold.ttf https://www.fedoraproject.org/fonts/montserrat/Montserrat-Bold.ttf — 86.9 KiB — 0 ms — font-display: swaphttps://www.fedoraproject.org/fonts/open-sans/OpenSans-Medium.ttfOpenSans-Medium.ttf https://www.fedoraproject.org/fonts/open-sans/OpenSans-Medium.ttf — 77.5 KiB — 0 ms — font-display: swaphttps://www.fedoraproject.org/fonts/open-sans/OpenSans-SemiBold.ttfOpenSans-SemiBold.ttf https://www.fedoraproject.org/fonts/open-sans/OpenSans-SemiBold.ttf — 77.1 KiB — 0 ms — font-display: swap
OpenSans-Regular.ttf ttf swap
Size 77 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
fa-solid-900.woff2 woff2 swap
Size 111 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
Montserrat-SemiBold.ttf ttf swap
Size 86 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
OpenSans-Bold.ttf ttf swap
Size 75 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Montserrat-Bold.ttf ttf swap
Size 87 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
OpenSans-Medium.ttf ttf swap
Size 78 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
OpenSans-SemiBold.ttf ttf swap
Size 77 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
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)

Fixing the unchecked items could save ~199 KB and ~398 ms

A+
JS Bundles
1 scripts, 0 KB unused
PASS
1 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.fedoraproject.org/js/darkmode.js1 KB—✓1st
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+
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
33 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
45% of JavaScript execution is third-party
First-party Third-party 243ms · 0KB · $3/mo
Unattributable
Other
Costly
Execution 243ms
Transfer 0 KB
Monthly Cost $3/mo

These scripts may cost more than they're worth

  • Unattributable adds 243ms and costs ~$3/month

45% 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 243ms 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

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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