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.
2.27 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
3.31 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.10 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.044
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
3.82 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.
4.55 s
Page Load Progression
FPage Weight BudgetAction5.9 MB transferred, 102 requestsFIX
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
Subset fonts to include only used characters, or switch to system font stacks.
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FJS Execution CostAction4392ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 3454ms | 2928ms | 0ms | 3rd |
| https://developers.line.biz/?r=/docs/line-social-plugins/ | 523ms | 121ms | 1ms | 3rd |
| https://developers.line.biz/_nuxt/CLNKnlQW.js | 160ms | 124ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-K94RFW73WS | 131ms | 109ms | 17ms | 3rd |
| https://developers.line.biz/_nuxt/CrbTXa04.js | 125ms | 105ms | 1ms | 3rd |
DPage Weight InventoryAction102 resources · 5.9 MB · 157 KB savings availableFIX
~157.1 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 102 resources | 5.9 MiB | ||||||
DHTTP CachingActionno-store (uncacheable)FIX
max-age=0, no-cache, no-store
| Directive | Value | Meaning |
|---|---|---|
| max-age | 0 | Cache for 0 seconds |
| no-cache | — | Cache but always revalidate first |
| no-store | — | Never cache this response |
BImage Optimization10 images, 0 KB saveableREVIEW
CJS BundlesAction58 scripts, 157 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-K94RFW73WS | 157 KB | 64 KB (41%) | ✓ | 3rd |
| https://developers.line.biz/_nuxt/Cxi3vQKm.js | 67 KB | 38 KB (57%) | ✓ | 3rd |
| https://developers.line.biz/_nuxt/prkPQDO6.js | 420 KB | 32 KB (10%) | ✓ | 3rd |
| https://developers.line.biz/_nuxt/CrbTXa04.js | 47 KB | 23 KB (50%) | ✓ | 3rd |
| https://developers.line.biz/_nuxt/Bgms0fH8.js | 1 KB | — | ✓ | 3rd |
| https://developers.line.biz/_nuxt/DlAUqK2U.js | 1 KB | — | ✓ | 3rd |
| https://developers.line.biz/_nuxt/C-4GxZT9.js | 4 KB | — | ✓ | 3rd |
| https://developers.line.biz/_nuxt/szH1qBxF.js | 13 KB | — | ✓ | 3rd |
| https://developers.line.biz/_nuxt/DPxYUU_D.js | 1 KB | — | ✓ | 3rd |
| https://developers.line.biz/_nuxt/DYgwRWPV.js | 2 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
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
A+Font Loading5 fonts (213 KB)PASS
Web fonts
5
213 KB total
Render-blocking
0
of 5
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
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 ~10 KB and ~20 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall102 requests over 11255msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 3454ms | 0 KB | — | ¥4772/mo | Costly |
developers.line.biz developers.line.biz | Other | 523ms | 11 KB | — | ¥723/mo | Costly |
developers.line.biz developers.line.biz | Other | 160ms | 2 KB | — | ¥221/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 131ms | 157 KB | 41% | ¥181/mo | Costly |
developers.line.biz developers.line.biz | Other | 125ms | 47 KB | 50% | ¥172/mo | Costly |
These scripts may cost more than they're worth
- Unattributable adds 3454ms and costs ~¥4772/month
- developers.line.biz adds 523ms and costs ~¥723/month
- developers.line.biz adds 160ms and costs ~¥221/month
- Google Tag Manager adds 131ms and costs ~¥181/month
- developers.line.biz adds 125ms and costs ~¥172/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
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
Unattributable takes 3454ms 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
developers.line.biz takes 523ms 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
developers.line.biz takes 160ms 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 131ms 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
developers.line.biz takes 125ms 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