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Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
82
GRADE
B
FIX
1
REVIEW
1
PASS
4
INFO
0
Device:
Mobile Desktop
Checks
6
4 PASS 1 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 Kestrel✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

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
0.40g CO2 per view
PASS
0.40g CO2 per view
Info::
0.40g CO2 per page view
This page transfers 1.4 MB, producing an estimated 0.40g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.07g, network 0.07g, end-user device 0.26g.
Got: 0.40g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 48.1 kg CO2/year
With 10,000 page views per month, this page would generate approximately 48.1 kg of CO2 annually — equivalent to charging 6018 smartphones.

0.40g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 70% of websites

Sustainable Web Design model v4 · Page size: 1.4 MB

Your site
0.40g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.07g
Network
0.07g
End-user device
0.26g
At 10,000 monthly views: Monthly: 4.0 kg · Annual: 48.1 kg · ≈ 6018 smartphone charges
A+
Repeat Visit Weight
84% cached
PASS
84% cached
Info::
84% reduction on repeat visits
Returning visitors download only 226 KB (vs 1450 KB first visit). 58 of 59 resources are served from browser cache, saving 0.34g CO2 per repeat visit.
Info::
Repeat visit: 0.06g CO2 (first visit: 0.40g)
First visit
1450 KB
Repeat visit
226 KB

84% reduction on repeat visits

Saving 0.34g CO2 per returning visitor

58 resources served from cache · 1 resources re-downloaded

A
Carbon Budget
30th percentile
PASS
30th percentile
Info::
0.40g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 70% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 30th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.40g

30th percentile

Cleaner than 70% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 33% cleaner ✓
vs Target 20% cleaner ✓
A+
Transfer Efficiency
90% efficient
PASS
90% efficient
Info::
Transfer efficiency: 90%
Only 140 KB of potential savings identified. Your page is well-optimized for size.
90% efficient

Total waste: 140 KB (10% of page weight)

Unused JS 140 KB

0.04g unnecessary CO2 per visit

Actual transfer 1450 KB
Theoretical minimum 1310 KB
Potential savings 140 KB (0.04g CO2)

See Deep Analysis sections above for specific optimizations.

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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