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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
84
GRADE
B
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 Not identified✗CDN Varnish✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

B
Transfer Efficiency
86% efficient
REVIEW
86% efficient
Info::
Transfer efficiency: 86%
An estimated 25 KB (14%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 25 KB of unused JavaScript. This wasted data produces 0.01g of unnecessary CO2 per page view.
86% efficient

Total waste: 25 KB (14% of page weight)

Unused JS 25 KB

0.01g unnecessary CO2 per visit

Actual transfer 188 KB
Theoretical minimum 162 KB
Potential savings 25 KB (0.01g 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
0.05g CO2 per view
PASS
0.05g CO2 per view
Info::
0.05g CO2 per page view
This page transfers 0.2 MB, producing an estimated 0.05g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.01g, end-user device 0.03g.
Got: 0.05g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 6.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 6.3 kg of CO2 annually — equivalent to charging 781 smartphones.

0.05g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 90% of websites

Sustainable Web Design model v4 · Page size: 0.2 MB

Your site
0.05g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.01g
End-user device
0.03g
At 10,000 monthly views: Monthly: 0.5 kg · Annual: 6.3 kg · ≈ 781 smartphone charges
A+
Repeat Visit Weight
93% cached
PASS
93% cached
Info::
93% reduction on repeat visits
Returning visitors download only 13 KB (vs 188 KB first visit). 14 of 15 resources are served from browser cache, saving 0.05g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.05g)
First visit
188 KB
Repeat visit
13 KB

93% reduction on repeat visits

Saving 0.05g CO2 per returning visitor

14 resources served from cache · 1 resources re-downloaded

A+
Carbon Budget
10th percentile
PASS
10th percentile
Info::
0.05g 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

0.05g

10th percentile

Cleaner than 90% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 91% cleaner ✓
vs Target 90% 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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