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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
91
GRADE
A
FIX
0
REVIEW
3
PASS
3
INFO
0
Device:
Mobile Desktop
Checks
6
3 PASS 3 REVIEW
B
CO2 Per Page Load
0.62g CO2 per view
REVIEW
0.62g CO2 per view
Info::
0.62g CO2 per page view
This page transfers 2.6 MB, producing an estimated 0.62g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.13g, end-user device 0.48g.
Got: 0.62g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 74.9 kg CO2/year
With 10,000 page views per month, this page would generate approximately 74.9 kg of CO2 annually — equivalent to charging 9363 smartphones.
Info::
Green hosting reduces data center emissions

0.62g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 50% of websites

Sustainable Web Design model v4 · Page size: 2.6 MB

Your site
0.62g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.02g
Network
0.13g
End-user device
0.48g
At 10,000 monthly views: Monthly: 6.2 kg · Annual: 74.9 kg · ≈ 9363 smartphone charges
B
Carbon Budget
50th percentile
REVIEW
50th percentile
Warning::
0.62g CO2 — above the median website (0.60g)
Heavier than an estimated 50% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 50th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.62g

50th percentile

Cleaner than 50% of websites

✗ Above the median website

vs Median 4% more
vs Target 25% more
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Green Hosting
Green (both)
PASS
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: GitHub Pages, CDN: Fastly
Info::
GitHub Pages: Hosted on Azure/GitHub with Microsoft carbon-negative commitment
Info::
Fastly: 100% renewable energy for edge network
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 Hosting✓ Green Hosted
Hosting GitHub Pages✓CDN Fastly✓

GitHub Pages: Hosted on Azure/GitHub with Microsoft carbon-negative commitment

Fastly: 100% renewable energy for edge network

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
100% cached
PASS
100% cached
Info::
100% reduction on repeat visits
Returning visitors download only 5 KB (vs 2700 KB first visit). 48 of 49 resources are served from browser cache, saving 0.62g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.62g)
First visit
2700 KB
Repeat visit
5 KB

100% reduction on repeat visits

Saving 0.62g CO2 per returning visitor

48 resources served from cache · 1 resources re-downloaded

A+
Transfer Efficiency
100% efficient
PASS
100% efficient
Info::
Transfer efficiency: 100%
Only 0 KB of potential savings identified. Your page is well-optimized for size.
100% efficient
Actual transfer 2700 KB
Theoretical minimum 2700 KB

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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