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https://mozillazine.org

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
93
GRADE
A
FIX
1
REVIEW
3
PASS
11
INFO
2

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

Mobile Desktop
82
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
88
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
69
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.

3.00 s

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

3.90 s

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

10 ms

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

0.038

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

3.00 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.

4.43 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
11 PASS 3 REVIEW 1 FIX
D
HTTP Caching
Action
no-store (uncacheable)
FIX
no-store (uncacheable)
Info::
Cache-Control: no-store prevents all caching
Intentional for dynamic content, but increases server load for every page view.
Got: no-store
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

no-store

DirectiveValueMeaning
no-store—Never cache this response
B
Image Optimization
7 images, 0 KB saveable
REVIEW
7 images, 0 KB saveable
Info::
All images are well-optimized
7 images 71 KB
0 oversized -0 KB
5 legacy format
0 missing dimensions CLS risk
C
JS Execution Cost
Action
1213ms total JS execution
REVIEW
1213ms total JS execution
Warning::
https://mozillazine.org/: 729ms CPU time
Warning::
Unattributable: 275ms CPU time
Info::
https://mozillazine.org/.within.website/x/cmd/anub...: 114ms CPU time
Info::
https://ssl.google-analytics.com/ga.js: 95ms CPU time
Info::
Third-party scripts: 370ms (31% of total)

Main Thread Breakdown

Other 57% Style & Layout 18% Script Evaluation 14% Rendering 8%
ScriptTotalScriptingParse/CompileParty
https://mozillazine.org/729ms12ms4ms1st
Unattributable275ms10ms0ms3rd
https://mozillazine.org/.within.website/x/cmd/anubis/static/js/main.mjs?cacheBuster=1.25.0114ms74ms0ms1st
https://ssl.google-analytics.com/ga.js95ms74ms19ms3rd
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
423 KB transferred, 22 requests
PASS
423 KB transferred, 22 requests
Info::
Page weighs 453 KB (423 KB transferred)
Info::
22 HTTP requests
Info::
Estimated 0.09 g CO2 per page load
423 KB / 2.4 MB budget
423 KB transferred
22 requests
0.09 g CO2 per page load
CSS 191.2 KiB 45%
Fonts 121.8 KiB 29%
Images 70.6 KiB 17%
JavaScript 23.3 KiB 6%
HTML 7.4 KiB 2%
Other 5.6 KiB 1%
Other 2.8 KiB 1%
0 2.4 MB 4.9 MB
Under budget
A
Third-Party Impact
33% third-party, 0 ms blocking
PASS
33% third-party, 0 ms blocking
Info::
Third-party code accounts for 33% of page weight (140.0 KiB of 422.7 KiB)
Info::
Third-party blocking time is low (0 ms)
67%
33%
First-party Third-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
2 fonts (122 KB)
PASS
2 fonts (122 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

122 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 1.0 s 2.0 s 3.0 s 4.0 s FCP 3.0 s LCP 3.9 sdata:font/woff2;base64,d09GMgABAAAAAOykABQAAAACdZgAAOwyAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGoUNG4LYfByR…woff2;base64,d09GMgABAA... data:font/woff2;base64,d09GMgABAAAAAOykABQAAAACdZgAAOwyAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGoUNG4LYfByR… — 59.2 KiB — 12 ms — font-display: swapdata:font/woff2;base64,d09GMgABAAAAAPq4ABUAAAACTIQAAPo7AAFmqAAAAAAAAAAAAAAAAAAAAAAAAAAAGokqG4Hrchya…woff2;base64,d09GMgABAA... data:font/woff2;base64,d09GMgABAAAAAPq4ABUAAAACTIQAAPo7AAFmqAAAAAAAAAAAAAAAAAAAAAAAAAAAGokqG4Hrchya… — 62.7 KiB — 14 ms — font-display: swap
woff2;base64,d09GMgABAA... woff2 swap
Size 59 KB
Load time 12 ms
Start 1.4 s
Risk FOUT — text flashes from fallback to web font
woff2;base64,d09GMgABAA... woff2 swap
Size 63 KB
Load time 14 ms
Start 1.4 s
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
6 scripts, 0 KB unused
PASS
6 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://mozillazine.org/.within.website/x/cmd/anubis/static/js/main.mjs?cacheBuster=1.25.06 KB—✓1st
https://mozillazine.org/.within.website/x/cmd/anubis/static/js/worker/sha256-webcrypto.mjs?cacheBuster=1.25.00 KB—✓1st
https://mozillazine.org/.within.website/x/cmd/anubis/static/js/worker/sha256-webcrypto.mjs?cacheBuster=1.25.00 KB—✓1st
http://www.google-analytics.com/urchin.js0 KB—✓3rd
https://ssl.google-analytics.com/ga.js17 KB—✓3rd
http://pagead2.googlesyndication.com/pagead/show_ads.js0 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
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A+
Page Weight Inventory
22 resources · 423 KB · 0 KB savings available
PASS
22 resources · 423 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 423 KB
Info::
7 third-party resources (33% of weight)
22 resources · 422.7 KiB · 7 third-party Within 1MB page-weight target
CSS 45% · 191.2 KiB
Font 29% · 121.8 KiB
Image 17% · 72.7 KiB
JavaScript 6% · 23.3 KiB
Document 2% · 8.0 KiB
Other 1% · 5.6 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
22 requests over 4097ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s FCP 3.0 s LCP 3.9 shttps://mozillazine.org// https://mozillazine.org/ — 200 — 2.6 KiB — 523 ms — h2https://mozillazine.org/.within.website/x/xess/xess.min.css?cachebuster=1.25.0/.within.website/x/xess/xess.min.cs... https://mozillazine.org/.within.website/x/xess/xess.min.css?cachebuster=1.25.0 — 200 — 190.4 KiB — 863 ms — h2https://mozillazine.org/.within.website/x/cmd/anubis/static/img/pensive.webp?cacheBuster=1.25.0/.within.website/x/cmd/anubis/stati... https://mozillazine.org/.within.website/x/cmd/anubis/static/img/pensive.webp?cacheBuster=1.25.0 — 200 — 28.3 KiB — 859 ms — h2https://mozillazine.org/.within.website/x/cmd/anubis/static/img/happy.webp?cacheBuster=1.25.0/.within.website/x/cmd/anubis/stati... https://mozillazine.org/.within.website/x/cmd/anubis/static/img/happy.webp?cacheBuster=1.25.0 — 200 — 30.0 KiB — 861 ms — h2https://mozillazine.org/.within.website/x/cmd/anubis/static/js/main.mjs?cacheBuster=1.25.0/.within.website/x/cmd/anubis/stati... https://mozillazine.org/.within.website/x/cmd/anubis/static/js/main.mjs?cacheBuster=1.25.0 — 200 — 5.8 KiB — 346 ms — h2https://mozillazine.org/.within.website/x/cmd/anubis/static/locales/en.json/.within.website/x/cmd/anubis/stati... https://mozillazine.org/.within.website/x/cmd/anubis/static/locales/en.json — 200 — 5.6 KiB — 341 ms — h2https://mozillazine.org/.within.website/x/cmd/anubis/static/js/worker/sha256-webcrypto.mjs?cacheBuster=1.25.0/.within.website/x/cmd/anubis/stati... https://mozillazine.org/.within.website/x/cmd/anubis/static/js/worker/sha256-webcrypto.mjs?cacheBuster=1.25.0 — 200 — 112 B — 350 ms — h2https://mozillazine.org/.within.website/x/cmd/anubis/static/js/worker/sha256-webcrypto.mjs?cacheBuster=1.25.0/.within.website/x/cmd/anubis/stati... https://mozillazine.org/.within.website/x/cmd/anubis/static/js/worker/sha256-webcrypto.mjs?cacheBuster=1.25.0 — 200 — 0 B — 347 ms — h2data:font/woff2;base64,d09GMgABAAAAAOykABQAAAACdZgAAOwyAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGoUNG4LYfByR…data:font/woff2;base64,d09GMgABAAAA... data:font/woff2;base64,d09GMgABAAAAAOykABQAAAACdZgAAOwyAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGoUNG4LYfByR… — 200 — 59.2 KiB — 12 ms — datadata:font/woff2;base64,d09GMgABAAAAAPq4ABUAAAACTIQAAPo7AAFmqAAAAAAAAAAAAAAAAAAAAAAAAAAAGokqG4Hrchya…data:font/woff2;base64,d09GMgABAAAA... data:font/woff2;base64,d09GMgABAAAAAPq4ABUAAAACTIQAAPo7AAFmqAAAAAAAAAAAAAAAAAAAAAAAAAAAGokqG4Hrchya… — 200 — 62.7 KiB — 14 ms — datahttps://mozillazine.org/favicon.ico/favicon.ico https://mozillazine.org/favicon.ico — 200 — 2.1 KiB — 176 ms — h2https://mozillazine.org/.within.website/x/cmd/anubis/api/pass-challenge?id=019db29a-8e11-7aab-86af-940bb27ffea1&response=00005ee82ae22df35932f31040173e0194e0df50d73cb0adc59234d1bdaa540e&nonce=259065&redir=https%3A%2F%2Fmozillazine.org%2F&elapsedTime=2135/.within.website/x/cmd/anubis/api/p... https://mozillazine.org/.within.website/x/cmd/anubis/api/pass-challenge?id=019db29a-8e11-7aab-86af-940bb27ffea1&response=00005ee82ae22df35932f31040173e0194e0df50d73cb0adc59234d1bdaa540e&nonce=259065&redir=https%3A%2F%2Fmozillazine.org%2F&elapsedTime=2135 — 302 — 661 B — 174 ms — h2https://mozillazine.org// https://mozillazine.org/ — 200 — 4.8 KiB — 179 ms — h2https://mozillazine.org/style/smallfront.css/style/smallfront.css https://mozillazine.org/style/smallfront.css — 200 — 865 B — 176 ms — h2https://mozillazine.org/image/new/title.gif/image/new/title.gif https://mozillazine.org/image/new/title.gif — 200 — 1.1 KiB — 175 ms — h2http://www.google-analytics.com/urchin.jswww.google-analytics.com/urchin.js http://www.google-analytics.com/urchin.js — -1 — 0 B — 0 ms — https://ssl.google-analytics.com/ga.jsssl.google-analytics.com/ga.js https://ssl.google-analytics.com/ga.js — 200 — 17.4 KiB — 98 ms — h2http://pagead2.googlesyndication.com/pagead/show_ads.jspagead2.googlesyndication.com/pagea... http://pagead2.googlesyndication.com/pagead/show_ads.js — -1 — 0 B — 0 ms — https://mozillazine.org/image/default/sky.png/image/default/sky.png https://mozillazine.org/image/default/sky.png — 200 — 8.6 KiB — 176 ms — h2https://mozillazine.org/image/default/blimp.png/image/default/blimp.png https://mozillazine.org/image/default/blimp.png — 200 — 1.7 KiB — 176 ms — h2https://ssl.google-analytics.com/r/__utm.gif?utmwv=5.7.2&utms=1&utmn=548310671&utmhn=mozillazine.org&utmcs=windows-1252&utmsr=412x823&utmvp=980x1957&utmsc=24-bit&utmul=en-us&utmje=0&utmfl=-&utmdt=mozillaZine&utmhid=382355870&utmr=0&utmp=%2F&utmht=1776817970206&utmac=UA-32170104-1&utmcc=__utma%3D4421167.1396642041.1776817970.1776817970.1776817970.1%3B%2B__utmz%3D4421167.1776817970.1.1.utmcsr%3D(direct)%7Cutmccn%3D(direct)%7Cutmcmd%3D(none)%3B&utmjid=249759603&utmredir=1&utmu=qBAAAAAAAAAAAAAAAAAAAAAE~ssl.google-analytics.com/r/__utm.gi... https://ssl.google-analytics.com/r/__utm.gif?utmwv=5.7.2&utms=1&utmn=548310671&utmhn=mozillazine.org&utmcs=windows-1252&utmsr=412x823&utmvp=980x1957&utmsc=24-bit&utmul=en-us&utmje=0&utmfl=-&utmdt=mozillaZine&utmhid=382355870&utmr=0&utmp=%2F&utmht=1776817970206&utmac=UA-32170104-1&utmcc=__utma%3D4421167.1396642041.1776817970.1776817970.1776817970.1%3B%2B__utmz%3D4421167.1776817970.1.1.utmcsr%3D(direct)%7Cutmccn%3D(direct)%7Cutmcmd%3D(none)%3B&utmjid=249759603&utmredir=1&utmu=qBAAAAAAAAAAAAAAAAAAAAAE~ — 200 — 365 B — 26 ms — h2https://ssl.google-analytics.com/__utm.gif?utmwv=5.7.2&utms=2&utmn=1449233781&utmhn=mozillazine.org&utmcs=windows-1252&utmsr=412x823&utmvp=980x1957&utmsc=24-bit&utmul=en-us&utmje=0&utmfl=-&utmdt=mozillaZine&utmhid=382355870&utmr=0&utmp=%2F&utmht=1776817970208&utmac=UA-21953982-1&utmcc=__utma%3D4421167.1396642041.1776817970.1776817970.1776817970.1%3B%2B__utmz%3D4421167.1776817970.1.1.utmcsr%3D(direct)%7Cutmccn%3D(direct)%7Cutmcmd%3D(none)%3B&utmjid=&utmmt=1&utmu=qBAAAAAAAAAAAAAAAAAAAAAE~ssl.google-analytics.com/__utm.gif?... https://ssl.google-analytics.com/__utm.gif?utmwv=5.7.2&utms=2&utmn=1449233781&utmhn=mozillazine.org&utmcs=windows-1252&utmsr=412x823&utmvp=980x1957&utmsc=24-bit&utmul=en-us&utmje=0&utmfl=-&utmdt=mozillaZine&utmhid=382355870&utmr=0&utmp=%2F&utmht=1776817970208&utmac=UA-21953982-1&utmcc=__utma%3D4421167.1396642041.1776817970.1776817970.1776817970.1%3B%2B__utmz%3D4421167.1776817970.1.1.utmcsr%3D(direct)%7Cutmccn%3D(direct)%7Cutmcmd%3D(none)%3B&utmjid=&utmmt=1&utmu=qBAAAAAAAAAAAAAAAAAAAAAE~ — 200 — 438 B — 25 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
31% of JavaScript execution is third-party
First-party Third-party 370ms · 17KB · $5/mo
Unattributable
Other
Costly
Execution 275ms
Transfer 0 KB
Monthly Cost $4/mo
Google Analytics
Analytics
Optional
Execution 95ms
Transfer 17 KB
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • Unattributable adds 275ms and costs ~$4/month

Unattributable takes 275ms 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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