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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
72
GRADE
C
FIX
2
REVIEW
1
PASS
3
INFO
0
Device:
Mobile Desktop
Checks
6
3 PASS 1 REVIEW 2 FIX
F
CO2 Per Page Load
Action
1.66g CO2 per view
FIX
1.66g CO2 per view
Warning::
1.66g CO2 per page view
This page transfers 7.0 MB, producing an estimated 1.66g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.04g, network 0.34g, end-user device 1.28g.
Got: 1.66g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 199.2 kg CO2/year
With 10,000 page views per month, this page would generate approximately 199.2 kg of CO2 annually — equivalent to charging 24903 smartphones.
Info::
Green hosting reduces data center emissions

1.66g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 20% of websites

Sustainable Web Design model v4 · Page size: 7.0 MB

Your site
1.66g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.04g
Network
0.34g
End-user device
1.28g
At 10,000 monthly views: Monthly: 16.6 kg · Annual: 199.2 kg · ≈ 24903 smartphone charges
F
Carbon Budget
Action
80th percentile
FIX
80th percentile
Warning::
1.66g CO2 — above the median website (0.60g)
Heavier than an estimated 20% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 80th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.66g

80th percentile

Cleaner than 20% of websites

✗ Above the median website

vs Median 177% more
vs Target 232% 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 31 KB (vs 7182 KB first visit). 136 of 137 resources are served from browser cache, saving 1.65g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 1.66g)
First visit
7182 KB
Repeat visit
31 KB

100% reduction on repeat visits

Saving 1.65g CO2 per returning visitor

136 resources served from cache · 1 resources re-downloaded

A+
Transfer Efficiency
96% efficient
PASS
96% efficient
Info::
Transfer efficiency: 96%
Only 282 KB of potential savings identified. Your page is well-optimized for size.
96% efficient

Total waste: 282 KB (4% of page weight)

Unused JS 282 KB

0.07g unnecessary CO2 per visit

Actual transfer 7182 KB
Theoretical minimum 6900 KB
Potential savings 282 KB (0.07g 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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