Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

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

Mobile Desktop

Performance

Accessibility

100

Best Practices

SEO

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

1.51 s

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

14.52 s

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

86 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.

1.51 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.

14.59 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

9 PASS 5 REVIEW 1 FIX

Page Weight Budget

Action

3.3 MB transferred, 39 requests

FIX

3.3 MB transferred, 39 requests

Page weighs 4.9 MB (3.3 MB transferred)

Images are 1.7 MB — compress or use modern formats

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Got: 1.7 MB

Fonts are 1.3 MB — consider subsetting or using system fonts

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

Got: 1.3 MB

39 HTTP requests

Estimated 0.70 g CO2 per page load

3.3 MB transferred

39 requests

0.70 g CO2 per page load

Images 1.7 MiB 51%

Fonts 1.3 MiB 39%

JavaScript 203.8 KiB 6%

CSS 83.9 KiB 2%

HTML 37.6 KiB 1%

Other 6.8 KiB 0%

Other 471 B 0%

0 2.4 MB 4.9 MB

Over budget

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.

Source: web.dev

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

Image Optimization

19 images, 0 KB saveable

REVIEW

19 images, 0 KB saveable

All images are well-optimized

19 images 1.7 MB

0 oversized -0 KB

5 legacy format

0 missing dimensions CLS risk

JS Execution Cost

Action

1340ms total JS execution

REVIEW

1340ms total JS execution

https://github.blog/: 831ms CPU time

Unattributable: 255ms CPU time

https://github.blog/_static/??/wp-content/themes/g...: 194ms CPU time

https://js.monitor.azure.com/scripts/c/ms.analytic...: 60ms CPU time

Third-party scripts: 315ms (24% of total)

Main Thread Breakdown

Style & Layout 35% Other 31% Script Evaluation 15% Rendering 8% Parse HTML & CSS 6% Script Parsing & Compilation 5%

Script	Total	Scripting	Parse/Compile	Party
https://github.blog/	831ms	19ms	2ms	1st
Unattributable	255ms	33ms	0ms	3rd
https://github.blog/_static/??/wp-content/themes/github-2021/dist/js/site-script.js,/wp-content/plugins/page-links-to/dist/new-tab.js?m=1776795618j	194ms	74ms	10ms	1st
https://js.monitor.azure.com/scripts/c/ms.analytics-web-4.js	60ms	11ms	47ms	3rd

JS Bundles

14 scripts, 90 KB unused

REVIEW

14 scripts, 90 KB unused

https://js.monitor.azure.com/scripts/c/ms.analytic...: 90 KB unused (88%)

Consider code splitting or tree shaking to reduce unused code.

https://js.monitor.azure.com/scripts/c/ms.analytic...: unminified — 38 KB could be saved

Total unused JavaScript: 90 KB

90 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://js.monitor.azure.com/scripts/c/ms.analytics-web-4.js	103 KB	90 KB (88%)	✗	3rd
https://github.blog/wp-includes/js/dist/url.min.js?m=1774626885g	4 KB	—	✓	1st
https://ghcc.githubassets.com/ghcc.min.js	18 KB	—	✓	3rd
https://github.blog/wp-includes/js/dist/script-modules/interactivity/index.min.js?ver=66c613f68580994bb00a	16 KB	—	✓	1st
https://github.blog/_static/??/wp-content/plugins/gh-cookie-consent-and-tracking/dist/js/cookie-consent-and-tracking.js,/wp-includes/js/dist/hooks.min.js?m=1776795618j	4 KB	—	✓	1st
https://github.blog/wp-includes/js/dist/i18n.min.js?ver=c26c3dc7bed366793375	3 KB	—	✓	1st
https://github.blog/wp-content/themes/github-2021/dist/blocks/category-filter/view-module.js?ver=c98e3bfa4bc2be7e7654	1 KB	—	✓	1st
https://github.blog/wp-includes/js/dist/api-fetch.min.js?ver=3a4d9af2b423048b0dee	3 KB	—	✓	1st
https://github.blog/_static/??/wp-content/themes/github-2021/dist/js/site-script.js,/wp-content/plugins/page-links-to/dist/new-tab.js?m=1776795618j	41 KB	—	✓	1st
https://analytics.githubassets.com/v1.1.0/hydro-marketing.min.js?ver=6.9.4	4 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

Page Weight Inventory

Action

39 resources · 3.3 MB · 90 KB savings available

REVIEW

39 resources · 3.3 MB · 90 KB savings available

Page weight 2.3 MB over 1MB target

Got: 3.3 MB Expected: ≤ 1 MB

~90 KB of savings available

9 third-party resources (4% of weight)

2 resources over 200KB

39 resources · 3.3 MiB · 9 third-party 2.3 MiB over 1MB target

Image 51% · 1.7 MiB

Font 39% · 1.3 MiB

JavaScript 6% · 203.8 KiB

CSS 2% · 83.9 KiB

Document 1% · 37.6 KiB

Other 0% · 471 B

~89.6 KiB of savings available

Remove unused JavaScript: 89.6 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

39 resources			3.3 MiB

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

A+

Third-Party Impact

4% third-party, 0 ms blocking

PASS

4% third-party, 0 ms blocking

Third-party code accounts for 4% of page weight (136.7 KiB of 3.3 MiB)

Third-party blocking time is low (0 ms)

96%

First-party Third-party

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

Font Loading

2 fonts (1337 KB)

PASS

2 fonts (1337 KB)

2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

1337 KB total

Render-blocking

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

mona-sans.woff2 woff2 swap

Size 134 KB

Load time 35 ms

Start 25 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

MonaspaceNeon-Regular.w... woff2 swap

Size 1203 KB

Load time 81 ms

Start 26 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

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 ~669 KB and ~1338 ms

A+

Resource Caching

All resources properly cached

PASS

All resources properly cached

No caching issues found

All static resources have appropriate caching headers.

A+

Critical Rendering Path

No render-blocking resources

PASS

No render-blocking resources

No render-blocking resources detected

A+

Resource Hints

7 hints, 0 missing preconnects

PASS

7 hints, 0 missing preconnects

Page uses 7 resource hint(s)

Current Resource Hints

preconnect

—

preload

dns-prefetch

prefetch

—

7 resource hints configured

A+

Render-Blocking Resources

No render-blocking resources detected

PASS

No render-blocking resources detected

No render-blocking resources detected in <head>

A+

Third-Party Resources

No third-party resources detected

PASS

No third-party resources detected

HTTP Caching

max-age=300 (5 minutes)

PASS

max-age=300 (5 minutes)

Cache-Control header is set

Got: max-age=300, must-revalidate

Effective TTL: 5 minutes (max-age=300)

No ETag or Last-Modified header

Conditional requests (304 Not Modified) are not possible without validators.

Cache-Control

max-age=300, must-revalidate

Directive	Value	Meaning
max-age	300	Cache for 5 minutes
must-revalidate	—	Must recheck with server after expiry

Effective TTL: 300 seconds

Network Waterfall

39 requests over 678ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Third-Party Script Cost

Per-script blocking time, transfer cost, and cache headers

INFO

24% of JavaScript execution is third-party

First-party Third-party 315ms · 103KB · $1/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
Unattributable Unattributable	Other	255ms	0 KB	—	$1/mo	Costly
js.monitor.azure.com js.monitor.azure.com	Other	60ms	103 KB	88%	$0/mo	Optional

Unattributable

Other

Costly

Execution 255ms

Transfer 0 KB

Monthly Cost $1/mo

js.monitor.azure.com

Other

Optional

Execution 60ms

Transfer 103 KB

Unused 88%

Monthly Cost $0/mo

These scripts may cost more than they're worth

Unattributable adds 255ms and costs ~$1/month

Unattributable takes 255ms 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

88% of js.monitor.azure.com'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.

Browse & Analyze

Learn

Performance

Page Load Progression

Green Hosting

Font loading timeline

Optimization checklist

These scripts may cost more than they're worth