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.
796 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.04 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
179 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.274
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.72 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.
2.96 s
Page Load Progression
FPage Weight BudgetAction3.3 MB transferred, 158 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
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
DPage Weight InventoryAction158 resources · 3.3 MB · 191 KB savings availableFIX
~190.8 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 158 resources | 3.3 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction106 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
CJS Execution CostAction1738ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.nikkei.com/ | 969ms | 7ms | 1ms | 3rd |
| Unattributable | 307ms | 4ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-PXS8451SBG | 152ms | 127ms | 17ms | 3rd |
| https://www.nikkei.com/.resources/k2-top/main.rev-727ad7f4.js | 119ms | 109ms | 1ms | 3rd |
| https://www.nikkei.com/.resources/tracking/static/atlas/atj.min.rev-c6c444.js | 110ms | 33ms | 1ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-1024704716&cx=c>m=4e64e1h1 | 82ms | 66ms | 13ms | 3rd |
CJS BundlesAction24 scripts, 191 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=AW-1024704716&cx=c>m=4e64e1h1 | 144 KB | 55 KB (38%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-PXS8451SBG | 174 KB | 55 KB (32%) | ✓ | 3rd |
| https://www.nikkei.com/.resources/k2-top/main.rev-727ad7f4.js | 134 KB | 48 KB (36%) | ✓ | 3rd |
| https://connect.facebook.net/en_US/fbevents.js | 96 KB | 32 KB (34%) | ✓ | 3rd |
| https://nkispa.nikkei.com/fh/showad_d094700e_d.js | 2 KB | — | ✓ | 3rd |
| https://partsa.nikkei.com/static/nkis/js/foneH.js | 3 KB | — | ✓ | 3rd |
| https://www.nikkei.com/.resources/tracking/static/atlas/atj.min.rev-c6c444.js | 7 KB | — | ✓ | 3rd |
| https://www.nikkei.com/.resources/tracking/static/atlas/c2p.rev-8c9198.js | 2 KB | — | ✓ | 3rd |
| https://www.nikkei.com/.resources/tracking/static/atlas/link-tracking.rev-c01db9.js | 1 KB | — | ✓ | 3rd |
| https://www.nikkei.com/.resources/tracking/static/atlas/google-analytics.rev-896d69.js | 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
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 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 Waterfall158 requests over 4096msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.nikkei.com www.nikkei.com | Other | 969ms | 72 KB | — | ¥1338/mo | Costly |
Unattributable Unattributable | Other | 307ms | 0 KB | — | ¥424/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 152ms | 174 KB | 32% | ¥210/mo | Costly |
www.nikkei.com www.nikkei.com | Other | 119ms | 134 KB | 36% | ¥164/mo | Costly |
www.nikkei.com www.nikkei.com | Other | 110ms | 7 KB | — | ¥152/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 82ms | 144 KB | 38% | ¥113/mo | Costly |
These scripts may cost more than they're worth
- www.nikkei.com adds 969ms and costs ~¥1338/month
- Unattributable adds 307ms and costs ~¥424/month
- Google Tag Manager adds 152ms and costs ~¥210/month
- www.nikkei.com adds 119ms and costs ~¥164/month
- www.nikkei.com adds 110ms and costs ~¥152/month
- Google Tag Manager adds 82ms and costs ~¥113/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.nikkei.com takes 969ms 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 307ms 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 152ms 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.nikkei.com takes 119ms 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.nikkei.com takes 110ms 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 82ms 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