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https://d.hatena.ne.jp

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
77
GRADE
C
FIX
1
REVIEW
2
PASS
3
INFO
0
Device:
Mobile Desktop
Checks
6
3 PASS 2 REVIEW 1 FIX
D
Green Hosting
Action
Not green
FIX
Not green
Info::
No confirmed renewable energy commitment detected
Consider providers like Cloudflare, Google Cloud, or Vercel that match 100% of their energy use with renewables.
Info::
Green hosting status based on known provider commitments
Green hosting detection uses a curated database of provider renewable energy commitments. This is not a real-time verification. For authoritative checks, visit thegreenwebfoundation.org.
Green HostingNot Green Hosted
Hosting Next.js✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

C
Transfer Efficiency
Action
68% efficient
REVIEW
68% efficient
Warning::
Transfer efficiency: 68%
An estimated 239 KB (32%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 239 KB of unused JavaScript. This wasted data produces 0.07g of unnecessary CO2 per page view.
68% efficient

Total waste: 239 KB (32% of page weight)

Unused JS 239 KB

0.07g unnecessary CO2 per visit

Actual transfer 739 KB
Theoretical minimum 500 KB
Potential savings 239 KB (0.07g CO2)

See Deep Analysis sections above for specific optimizations.

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A
CO2 Per Page Load
0.20g CO2 per view
PASS
0.20g CO2 per view
Info::
0.20g CO2 per page view
This page transfers 0.7 MB, producing an estimated 0.20g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.04g, network 0.04g, end-user device 0.13g.
Got: 0.20g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 24.5 kg CO2/year
With 10,000 page views per month, this page would generate approximately 24.5 kg of CO2 annually — equivalent to charging 3067 smartphones.

0.20g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 90% of websites

Sustainable Web Design model v4 · Page size: 0.7 MB

Your site
0.20g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.04g
Network
0.04g
End-user device
0.13g
At 10,000 monthly views: Monthly: 2.0 kg · Annual: 24.5 kg · ≈ 3067 smartphone charges
A+
Repeat Visit Weight
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 8 KB (vs 739 KB first visit). 21 of 22 resources are served from browser cache, saving 0.20g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.20g)
First visit
739 KB
Repeat visit
8 KB

99% reduction on repeat visits

Saving 0.20g CO2 per returning visitor

21 resources served from cache · 1 resources re-downloaded

A+
Carbon Budget
10th percentile
PASS
10th percentile
Info::
0.20g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 90% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 10th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.20g

10th percentile

Cleaner than 90% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 66% cleaner ✓
vs Target 59% cleaner ✓
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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