Performance
· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
964 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.24 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
70 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.078
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.31 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.
3.14 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 sDThird-Party ImpactAction99% third-party, 0 ms blockingFIX
CImage OptimizationAction10 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
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.
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.
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.
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.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
BJS Execution Cost531ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://d.hatena.ne.jp/ | 180ms | 2ms | 0ms | 1st |
| https://live.blog-tags.st-hatena.com/_next/static/chunks/commons.d78459f0c3cff869b62b.js | 109ms | 89ms | 19ms | 3rd |
| Unattributable | 106ms | 27ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=UA-46136157-1 | 69ms | 54ms | 15ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-DWG0LC0DR1&cx=c>m=4e64k0 | 66ms | 47ms | 18ms | 3rd |
CJS BundlesAction8 scripts, 239 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://live.blog-tags.st-hatena.com/_next/static/chunks/commons.d78459f0c3cff869b62b.js | 164 KB | 92 KB (56%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=UA-46136157-1 | 125 KB | 64 KB (51%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-DWG0LC0DR1&cx=c>m=4e64k0 | 146 KB | 63 KB (43%) | ✓ | 3rd |
| https://live.blog-tags.st-hatena.com/_next/static/ecCy-ZoXLhV5wFwpEDUKj/pages/_app.js | 26 KB | 20 KB (80%) | ✓ | 3rd |
| https://live.blog-tags.st-hatena.com/_next/static/ecCy-ZoXLhV5wFwpEDUKj/pages/index.js | 8 KB | — | ✓ | 3rd |
| https://live.blog-tags.st-hatena.com/_next/static/runtime/webpack-035ac2b14bde147cb4a8.js | 1 KB | — | ✓ | 3rd |
| https://live.blog-tags.st-hatena.com/_next/static/runtime/main-389f2d5a5a59288bda75.js | 5 KB | — | ✓ | 3rd |
| https://www.google-analytics.com/analytics.js | 21 KB | — | ✓ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
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.
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.
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.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
BPage Weight Inventory22 resources · 740 KB · 239 KB savings availableREVIEW
~239.2 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 22 resources | 739.5 KiB | ||||||
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
BHTTP Cachingno-cacheREVIEW
no-cache
| Directive | Value | Meaning |
|---|---|---|
| no-cache | — | Cache but always revalidate first |
APage Weight Budget740 KB transferred, 22 requestsPASS
A+Text CompressionAll text resources are compressedPASS
A+Font LoadingNo web fonts (system fonts)PASS
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall22 requests over 3365msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
live.blog-tags.st-hatena.com live.blog-tags.st-hatena.com | Other | 109ms | 164 KB | 56% | ¥151/mo | Costly |
Unattributable Unattributable | Other | 106ms | 0 KB | — | ¥147/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 69ms | 125 KB | 51% | ¥96/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 66ms | 146 KB | 43% | ¥92/mo | Costly |
These scripts may cost more than they're worth
- live.blog-tags.st-hatena.com adds 109ms and costs ~¥151/month
- Unattributable adds 106ms and costs ~¥147/month
- Google Tag Manager adds 69ms and costs ~¥96/month
- Google Tag Manager adds 66ms and costs ~¥92/month
66% of JavaScript execution time comes from third-party scripts.
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
live.blog-tags.st-hatena.com takes 109ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
56% of live.blog-tags.st-hatena.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
Unattributable takes 106ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 69ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
51% of Google Tag Manager's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
Google Tag Manager takes 66ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev