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.
C
Image Optimization
Action
100 images, 0 KB saveable
REVIEW
100 images, 0 KB saveable
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gfooter-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gfooter-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/top/img/today-bnr--pc.... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/top/img/switch2_poko-a... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gfooter-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/top/img/super-mario-ga... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gfooter-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gfooter-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gfooter-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/top/img/switch_tomodac... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/top/img/pikmin_garden_... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/top/img/switch2_splato... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gfoter-a... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gheader-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.nintendo.com/jp/common/v3/img/gfooter-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
100images5.1 MB
0oversized-0 KB
27legacy format
41missing dimensionsCLS risk
Set explicit width and height to prevent CLS.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
C
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
Info::
✓
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
5 fonts (1037 KB)
PASS
5 fonts (1037 KB)
Info::
i
5 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
5
1037 KB total
Render-blocking
0
of 5
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
YakuHanJPs-Bold.woff2woff2swap
Size4 KB
Load time4 ms
Start951 ms
RiskFOUT — text flashes from fallback to web font
YakuHanJPs-Regular.woff2woff2swap
Size3 KB
Load time4 ms
Start952 ms
RiskFOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a...woff2swap
Size37 KB
Load time49 ms
Start952 ms
RiskFOUT — text flashes from fallback to web font
NotoSansJP-Bold.woff2woff2swap
Size501 KB
Load time15 ms
Start1.2 s
RiskFOUT — 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
NotoSansJP-Regular.woff2woff2swap
Size493 KB
Load time21 ms
Start1.2 s
RiskFOUT — 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 ~497 KB and ~994 ms
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
✓
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
✓
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
✓
No resource hint issues
Network Waterfall
170 requests over 4134ms
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-party2047ms · 1912KB · ¥5278/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
www.nintendo.com
www.nintendo.com
Other
941ms
156 KB
43%
¥2426/mo
Costly
www.nintendo.com
www.nintendo.com
Other
335ms
5 KB
—
¥863/mo
Costly
Unattributable
Unattributable
Other
246ms
0 KB
—
¥635/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
212ms
193 KB
34%
¥547/mo
Costly
cdn.accounts.nintendo.com
cdn.accounts.nintendo.com
Other
123ms
1388 KB
42%
¥317/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
102ms
167 KB
39%
¥263/mo
Costly
cdn.accounts.nintendo.com
cdn.accounts.nintendo.com
Other
89ms
3 KB
—
¥228/mo
Costly
www.nintendo.com
Other
Costly
Execution941ms
Transfer156 KB
Unused43%
Monthly Cost¥2426/mo
www.nintendo.com
Other
Costly
Execution335ms
Transfer5 KB
Monthly Cost¥863/mo
Unattributable
Other
Costly
Execution246ms
Transfer0 KB
Monthly Cost¥635/mo
Google Tag Manager
Tag Manager
Costly
Execution212ms
Transfer193 KB
Unused34%
Monthly Cost¥547/mo
cdn.accounts.nintendo.com
Other
Costly
Execution123ms
Transfer1388 KB
Unused42%
Monthly Cost¥317/mo
Google Tag Manager
Tag Manager
Costly
Execution102ms
Transfer167 KB
Unused39%
Monthly Cost¥263/mo
cdn.accounts.nintendo.com
Other
Costly
Execution89ms
Transfer3 KB
Monthly Cost¥228/mo
These scripts may cost more than they're worth
www.nintendo.com adds 941ms and costs ~¥2426/month
www.nintendo.com adds 335ms and costs ~¥863/month
Unattributable adds 246ms and costs ~¥635/month
Google Tag Manager adds 212ms and costs ~¥547/month
cdn.accounts.nintendo.com adds 123ms and costs ~¥317/month
Google Tag Manager adds 102ms and costs ~¥263/month
cdn.accounts.nintendo.com adds 89ms and costs ~¥228/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.nintendo.com takes 941ms 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
www.nintendo.com takes 335ms 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 246ms 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 212ms 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
cdn.accounts.nintendo.com takes 123ms 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 102ms 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
cdn.accounts.nintendo.com takes 89ms 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.
771 ms
1.5 s
2.3 s
3.1 s
3.9 s
5.4 s
6.2 s