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.
1.75 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
3.15 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
24 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
1.000
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.62 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.
3.17 s
Page Load Progression
FPage Weight BudgetAction3.9 MB transferred, 118 requestsFIX
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
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
DJS BundlesAction27 scripts, 380 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-NVWP7LRL3Y&cx=c>m=4e64k1 | 151 KB | 108 KB (72%) | ✓ | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604200101/pubads_impl.js?cb=31097964 | 188 KB | 106 KB (56%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-NVWP7LRL3Y | 151 KB | 66 KB (44%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=UA-3501429-1 | 116 KB | 63 KB (55%) | ✓ | 3rd |
| https://fundingchoicesmessages.google.com/i/164746869?ers=3 | 70 KB | 36 KB (53%) | ✓ | 3rd |
| https://www.japan-guide.com/public/js/jg/pages/homepage.59c9f928a34542e7a6860c81333ab68e.min.js | 0 KB | — | ✓ | 3rd |
| https://www.japan-guide.com/public/js/jg/components/mega_menu.9cbd42e854bae4f4fad6831a12655cab.min.js | 2 KB | — | ✓ | 3rd |
| https://securepubads.g.doubleclick.net/tag/js/gpt.js | 34 KB | — | ✓ | 3rd |
| https://js.adara.com/index.js | 7 KB | — | ✓ | 3rd |
| https://fundingchoicesmessages.google.com/f/AGSKWxV2di7vNPNvR7EObaSMrwwp14bk5jVs8arwhZVdoNytvKesFIUMifHIviZOYSCOL0HJHFkVQUt0_LcA-ROV3OqQrkMOCvDK4gO7vpB2etmfdiCmkQdqFDEqXBt3IA8Pzum5L7jq6A==?fccs=W251bGwsbnVsbCxudWxsLG51bGwsbnVsbCxudWxsLFsxNzc2OTAwODYxLDYyNzAwMDAwMF0sbnVsbCxudWxsLG51bGwsW251bGwsWzddXSwiaHR0cHM6Ly93d3cuamFwYW4tZ3VpZGUuY29tLyIsbnVsbCxbWzgsInBTSmtvMTk2SUgwIl0sWzksImVuLVVTIl0sWzE4LCJbW1tudWxsLDEzMjJdXV0iXSxbMzUsIjE3NzY5MDA4NjEiXSxbMjYsIjE4Il0sWzE5LCIyIl0sWzE3LCJbMF0iXSxbMjQsIiJdLFsyNSwiW1s5NTM4NjE4OV1dIl0sWzI5LCJmYWxzZSJdXV0 | 1 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
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
DPage Weight InventoryAction118 resources · 3.9 MB · 380 KB savings availableFIX
~379.6 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 118 resources | 3.9 MiB | ||||||
CImage OptimizationAction38 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
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
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
CJS Execution CostAction1763ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.japan-guide.com/public/js/jg/main.008c46eb48a1209d29ef7380c0bceafd.min.js | 629ms | 265ms | 17ms | 3rd |
| https://www.japan-guide.com/ | 382ms | 21ms | 1ms | 3rd |
| Unattributable | 283ms | 50ms | 0ms | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604200101/pubads_impl.js?cb=31097964 | 234ms | 116ms | 21ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-NVWP7LRL3Y | 109ms | 64ms | 16ms | 3rd |
| https://fundingchoicesmessages.google.com/i/164746869?ers=3 | 76ms | 67ms | 7ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=UA-3501429-1 | 50ms | 39ms | 11ms | 3rd |
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
BHTTP Cachingmax-age=0REVIEW
max-age=0
| Directive | Value | Meaning |
|---|---|---|
| max-age | 0 | Cache for 0 seconds |
A+Text CompressionAll text resources are compressedPASS
A+Font Loading3 fonts (200 KB)PASS
Web fonts
3
200 KB total
Render-blocking
0
of 3
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
- 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 ~60 KB and ~120 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall118 requests over 4893msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.japan-guide.com www.japan-guide.com | Other | 629ms | 33 KB | — | $8/mo | Costly |
www.japan-guide.com www.japan-guide.com | Other | 382ms | 45 KB | — | $5/mo | Costly |
Unattributable Unattributable | Other | 283ms | 0 KB | — | $4/mo | Costly |
securepubads.g.doubleclick.net securepubads.g.doubleclick.net | Other | 234ms | 188 KB | 56% | $3/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 109ms | 151 KB | 44% | $1/mo | Optional |
fundingchoicesmessages.google.com fundingchoicesmessages.google.com | Other | 76ms | 70 KB | 53% | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 50ms | 116 KB | 55% | $1/mo | Optional |
These scripts may cost more than they're worth
- www.japan-guide.com adds 629ms and costs ~$8/month
- www.japan-guide.com adds 382ms and costs ~$5/month
- Unattributable adds 283ms and costs ~$4/month
- securepubads.g.doubleclick.net adds 234ms and costs ~$3/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
www.japan-guide.com takes 629ms 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
www.japan-guide.com takes 382ms 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
Unattributable takes 283ms 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
securepubads.g.doubleclick.net takes 234ms 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 securepubads.g.doubleclick.net'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
53% of fundingchoicesmessages.google.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
55% 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