Performance

· 15 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

100

Accessibility

100

Best Practices

100

SEO

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

2.81 s

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

3.07 s

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

4 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.

3.03 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.

3.45 s

Page Load Progression

469 ms

939 ms

1.4 s

1.9 s

2.3 s

2.8 s

3.3 s

3.8 s

Checks

5 PASS 4 REVIEW 4 FIX

Page Weight Budget

Action

3.3 MB transferred, 57 requests

FIX

3.3 MB transferred, 57 requests

Page weighs 4.2 MB (3.3 MB transferred)

Images are 2.8 MB — compress or use modern formats

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

Got: 2.8 MB

57 HTTP requests

Estimated 0.69 g CO2 per page load

3.3 MB transferred

57 requests

0.69 g CO2 per page load

Images 2.8 MiB 84%

JavaScript 305.8 KiB 9%

Fonts 153.4 KiB 5%

CSS 34.2 KiB 1%

Other 31.9 KiB 1%

HTML 22.9 KiB 1%

Other 548 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

Third-Party Impact

Action

100% third-party, 0 ms blocking

FIX

100% third-party, 0 ms blocking

Third-party code accounts for 100% of page weight (3.3 MiB of 3.3 MiB)

Third-party blocking time is low (0 ms)

100%

First-party Third-party

Page Weight Inventory

Action

57 resources · 3.3 MB · 129 KB savings available

FIX

57 resources · 3.3 MB · 129 KB savings available

Page weight 2.3 MB over 1MB target

Got: 3.3 MB Expected: ≤ 1 MB

~129 KB of savings available

56 third-party resources (100% of weight)

2 resources over 200KB

57 resources · 3.3 MiB · 56 third-party 2.3 MiB over 1MB target

Image 85% · 2.8 MiB

JavaScript 9% · 305.8 KiB

Font 5% · 153.4 KiB

CSS 1% · 34.2 KiB

Document 1% · 23.0 KiB

Other 0% · 1.1 KiB

~129.0 KiB of savings available

Remove unused JavaScript: 129.0 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

57 resources			3.3 MiB

HTTP Caching

Action

No cache headers

FIX

No cache headers

No Cache-Control header found

Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

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

Image Optimization

45 images, 0 KB saveable

REVIEW

45 images, 0 KB saveable

All images are well-optimized

45 images 2.8 MB

0 oversized -0 KB

45 legacy format

0 missing dimensions CLS risk

JS Execution Cost

550ms total JS execution

REVIEW

550ms total JS execution

https://www.exblog.jp/: 337ms CPU time

Unattributable: 103ms CPU time

https://www.googletagmanager.com/gtag/js?id=G-SK7D...: 60ms CPU time

https://www.googletagmanager.com/gtm.js?id=GTM-MSP...: 51ms CPU time

Third-party scripts: 550ms (100% of total)

Main Thread Breakdown

Style & Layout 47% Script Evaluation 22% Other 17% Script Parsing & Compilation 7% Parse HTML & CSS 3% Rendering 3%

Script	Total	Scripting	Parse/Compile	Party
https://www.exblog.jp/	337ms	5ms	0ms	3rd
Unattributable	103ms	28ms	0ms	3rd
https://www.googletagmanager.com/gtag/js?id=G-SK7DRSBW10&cx=c&gtm=4e64h1	60ms	38ms	22ms	3rd
https://www.googletagmanager.com/gtm.js?id=GTM-MSPWGQ	51ms	38ms	12ms	3rd

JS Bundles

4 scripts, 129 KB unused

REVIEW

4 scripts, 129 KB unused

https://www.googletagmanager.com/gtm.js?id=GTM-MSP...: 66 KB unused (52%)

Consider code splitting or tree shaking to reduce unused code.

https://www.googletagmanager.com/gtag/js?id=G-SK7D...: 63 KB unused (43%)

Consider code splitting or tree shaking to reduce unused code.

Total unused JavaScript: 129 KB

129 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://www.googletagmanager.com/gtm.js?id=GTM-MSPWGQ	127 KB	66 KB (52%)	✓	3rd
https://www.googletagmanager.com/gtag/js?id=G-SK7DRSBW10&cx=c&gtm=4e64h1	147 KB	63 KB (43%)	✓	3rd
https://s.eximg.jp/exblog/js/htmx.min.js	16 KB	—	✓	3rd
https://s.eximg.jp/exblog/js/alpine.min.js	16 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

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

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

Font Loading

1 fonts (153 KB)

PASS

1 fonts (153 KB)

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

Web fonts

153 KB total

Render-blocking

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

fa-solid-900.woff2 woff2 swap

Size 153 KB

Load time 54 ms

Start 2.6 s

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 ~77 KB and ~154 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

No optimization needed

PASS

No optimization needed

No resource hint issues

Network Waterfall

57 requests over 2999ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Third-Party Script Cost

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

INFO

100% of JavaScript execution is third-party

First-party Third-party 550ms · 296KB · ¥761/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
www.exblog.jp www.exblog.jp	Other	337ms	23 KB	—	¥466/mo	Costly
Unattributable Unattributable	Other	103ms	0 KB	—	¥142/mo	Costly
Google Tag Manager www.googletagmanager.com	Tag Manager	60ms	147 KB	43%	¥83/mo	Costly
Google Tag Manager www.googletagmanager.com	Tag Manager	51ms	127 KB	52%	¥70/mo	Costly

www.exblog.jp

Other

Costly

Execution 337ms

Transfer 23 KB

Monthly Cost ¥466/mo

Unattributable

Other

Costly

Execution 103ms

Transfer 0 KB

Monthly Cost ¥142/mo

Google Tag Manager

Tag Manager

Costly

Execution 60ms

Transfer 147 KB

Unused 43%

Monthly Cost ¥83/mo

Google Tag Manager

Tag Manager

Costly

Execution 51ms

Transfer 127 KB

Unused 52%

Monthly Cost ¥70/mo

These scripts may cost more than they're worth

www.exblog.jp adds 337ms and costs ~¥466/month
Unattributable adds 103ms and costs ~¥142/month
Google Tag Manager adds 60ms and costs ~¥83/month
Google Tag Manager adds 51ms and costs ~¥70/month

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

www.exblog.jp takes 337ms 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

Unattributable takes 103ms 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

Google Tag Manager takes 60ms 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

Google Tag Manager takes 51ms 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

52% 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.