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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
Carbon Budget
Action
53th percentile
FIX
53th percentile
Warning::
0.73g CO2 — above the median website (0.60g)
Heavier than an estimated 47% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 53th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.73g

53rd percentile

Cleaner than 47% of websites

✗ Above the median website

vs Median 22% more
vs Target 46% more
B
CO2 Per Page Load
0.73g CO2 per view
REVIEW
0.73g CO2 per view
Info::
0.73g CO2 per page view
This page transfers 3.1 MB, producing an estimated 0.73g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.15g, end-user device 0.56g.
Got: 0.73g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 87.5 kg CO2/year
With 10,000 page views per month, this page would generate approximately 87.5 kg of CO2 annually — equivalent to charging 10938 smartphones.
Info::
Green hosting reduces data center emissions

0.73g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 47% of websites

Sustainable Web Design model v4 · Page size: 3.1 MB

Your site
0.73g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.02g
Network
0.15g
End-user device
0.56g
At 10,000 monthly views: Monthly: 7.3 kg · Annual: 87.5 kg · ≈ 10938 smartphone charges
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 13 KB (vs 3155 KB first visit). 69 of 71 resources are served from browser cache, saving 0.73g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.73g)
First visit
3155 KB
Repeat visit
13 KB

100% reduction on repeat visits

Saving 0.73g CO2 per returning visitor

69 resources served from cache · 2 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 3155 KB
Theoretical minimum 3155 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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