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https://libera.chat

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
99
GRADE
A+
FIX
0
REVIEW
1
PASS
14
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.
95
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.
92
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.

789 ms

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

1.35 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.

0.000

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

789 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.

1.35 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
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
146 KB transferred, 12 requests
PASS
146 KB transferred, 12 requests
Info::
Page weighs 172 KB (146 KB transferred)
Info::
12 HTTP requests
Info::
Estimated 0.03 g CO2 per page load
146 KB / 2.4 MB budget
146 KB transferred
12 requests
0.03 g CO2 per page load
Fonts 134.2 KiB 92%
HTML 7.4 KiB 5%
CSS 1.3 KiB 1%
Other 1.2 KiB 1%
Images 1.2 KiB 1%
JavaScript 502 B 0%
0 2.4 MB 4.9 MB
Under budget
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
Image Optimization
1 images, 0 KB saveable
PASS
1 images, 0 KB saveable
Warning::
https://libera.chat/static/img/libera-color.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
1 images 1 KB
0 oversized -0 KB
1 legacy format
1 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

A+
JS Execution Cost
268ms total JS execution
PASS
268ms total JS execution
Info::
https://libera.chat/: 161ms CPU time
Info::
Unattributable: 106ms CPU time
Info::
Third-party scripts: 106ms (40% of total)

Main Thread Breakdown

Style & Layout 44% Other 41% Rendering 6% Script Evaluation 5% Parse HTML & CSS 4%
ScriptTotalScriptingParse/CompileParty
https://libera.chat/161ms6ms1ms1st
Unattributable106ms5ms0ms3rd
A+
Font Loading
6 fonts (134 KB)
PASS
6 fonts (134 KB)
Info::
6 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

6

134 KB total

Render-blocking

0

of 6

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s FCP 789 ms LCP 1.4 shttps://libera.chat/static/fonts/comfortaa-v30-subset-regular.woff2comfortaa-v30-subset-re... https://libera.chat/static/fonts/comfortaa-v30-subset-regular.woff2 — 5.1 KiB — 5 ms — font-display: swaphttps://libera.chat/static/fonts/ubuntu-v15-latin-regular.woff2ubuntu-v15-latin-regula... https://libera.chat/static/fonts/ubuntu-v15-latin-regular.woff2 — 33.7 KiB — 126 ms — font-display: swaphttps://libera.chat/static/fonts/ubuntu-v15-subset-500.woff2ubuntu-v15-subset-500.w... https://libera.chat/static/fonts/ubuntu-v15-subset-500.woff2 — 4.0 KiB — 4 ms — font-display: swaphttps://libera.chat/static/fonts/ubuntu-v15-latin-500.woff2ubuntu-v15-latin-500.woff2 https://libera.chat/static/fonts/ubuntu-v15-latin-500.woff2 — 29.4 KiB — 218 ms — font-display: swaphttps://libera.chat/static/fonts/ubuntu-v15-latin-italic.woff2ubuntu-v15-latin-italic... https://libera.chat/static/fonts/ubuntu-v15-latin-italic.woff2 — 35.3 KiB — 5 ms — font-display: swaphttps://libera.chat/static/fonts/ubuntu-mono-v10-latin-regular.woff2ubuntu-mono-v10-latin-r... https://libera.chat/static/fonts/ubuntu-mono-v10-latin-regular.woff2 — 26.8 KiB — 4 ms — font-display: swap
comfortaa-v30-subset-re... woff2 swap
Size 5 KB
Load time 5 ms
Start 20 ms
Risk FOUT — text flashes from fallback to web font
ubuntu-v15-latin-regula... woff2 swap
Size 34 KB
Load time 126 ms
Start 21 ms
Risk FOUT — text flashes from fallback to web font
ubuntu-v15-subset-500.w... woff2 swap
Size 4 KB
Load time 4 ms
Start 21 ms
Risk FOUT — text flashes from fallback to web font
ubuntu-v15-latin-500.woff2 woff2 swap
Size 29 KB
Load time 218 ms
Start 167 ms
Risk FOUT — text flashes from fallback to web font
ubuntu-v15-latin-italic... woff2 swap
Size 35 KB
Load time 5 ms
Start 183 ms
Risk FOUT — text flashes from fallback to web font
ubuntu-mono-v10-latin-r... woff2 swap
Size 27 KB
Load time 4 ms
Start 184 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
1 scripts, 0 KB unused
PASS
1 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://libera.chat/static/js/header-links.js0 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
4 hints, 0 missing preconnects
PASS
4 hints, 0 missing preconnects
Info::
Page uses 4 resource hint(s)

Current Resource Hints

preconnect
—
preload
4
dns-prefetch
—
prefetch
—

4 resource hints configured

A+
Page Weight Inventory
12 resources · 146 KB · 0 KB savings available
PASS
12 resources · 146 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 146 KB
12 resources · 145.8 KiB · 0 third-party Within 1MB page-weight target
Font 92% · 134.2 KiB
Document 5% · 7.4 KiB
Image 2% · 2.4 KiB
CSS 1% · 1.3 KiB
JavaScript 0% · 502 B
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+
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
12 requests over 396ms
INFO
0 ms 500 ms 1.0 s FCP 789 ms LCP 1.4 shttps://libera.chat// https://libera.chat/ — 200 — 7.4 KiB — 10 ms — h2https://libera.chat/static/fonts/comfortaa-v30-subset-regular.woff2/static/fonts/comfortaa-v30-subset-... https://libera.chat/static/fonts/comfortaa-v30-subset-regular.woff2 — 200 — 5.1 KiB — 5 ms — h2https://libera.chat/static/fonts/ubuntu-v15-latin-regular.woff2/static/fonts/ubuntu-v15-latin-regu... https://libera.chat/static/fonts/ubuntu-v15-latin-regular.woff2 — 200 — 33.7 KiB — 126 ms — h2https://libera.chat/static/fonts/ubuntu-v15-subset-500.woff2/static/fonts/ubuntu-v15-subset-500... https://libera.chat/static/fonts/ubuntu-v15-subset-500.woff2 — 200 — 4.0 KiB — 4 ms — h2https://libera.chat/static/css/additional-styles.css/static/css/additional-styles.css https://libera.chat/static/css/additional-styles.css — 200 — 1.3 KiB — 132 ms — h2https://libera.chat/static/img/libera-color.svg/static/img/libera-color.svg https://libera.chat/static/img/libera-color.svg — 200 — 1.2 KiB — 4 ms — h2https://libera.chat/static/js/header-links.js/static/js/header-links.js https://libera.chat/static/js/header-links.js — 200 — 502 B — 2 ms — h2https://libera.chat/static/fonts/ubuntu-v15-latin-500.woff2/static/fonts/ubuntu-v15-latin-500.... https://libera.chat/static/fonts/ubuntu-v15-latin-500.woff2 — 200 — 29.4 KiB — 218 ms — h2https://libera.chat/static/fonts/ubuntu-v15-latin-italic.woff2/static/fonts/ubuntu-v15-latin-ital... https://libera.chat/static/fonts/ubuntu-v15-latin-italic.woff2 — 200 — 35.3 KiB — 5 ms — h2https://libera.chat/static/fonts/ubuntu-mono-v10-latin-regular.woff2/static/fonts/ubuntu-mono-v10-latin... https://libera.chat/static/fonts/ubuntu-mono-v10-latin-regular.woff2 — 200 — 26.8 KiB — 4 ms — h2https://libera.chat/favicon.ico/favicon.ico https://libera.chat/favicon.ico — 200 — 1.2 KiB — 2 ms — h2https://libera.chat/static/img/libera-color.svg/static/img/libera-color.svg https://libera.chat/static/img/libera-color.svg — 200 — 0 B — 1 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
40% of JavaScript execution is third-party
First-party Third-party 106ms · 0KB · €0/mo
Unattributable
Other
Optional
Execution 106ms
Transfer 0 KB
Monthly Cost €0/mo

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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