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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
76
GRADE
C
FIX
2
REVIEW
2
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 2 REVIEW 2 FIX
D
CO2 Per Page Load
Action
1.16g CO2 per view
FIX
1.16g CO2 per view
Warning::
1.16g CO2 per page view
This page transfers 4.9 MB, producing an estimated 1.16g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.03g, network 0.24g, end-user device 0.89g.
Got: 1.16g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 139.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 139.8 kg of CO2 annually — equivalent to charging 17472 smartphones.
Info::
Green hosting reduces data center emissions

1.16g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 34% of websites

Sustainable Web Design model v4 · Page size: 4.9 MB

Your site
1.16g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.03g
Network
0.24g
End-user device
0.89g
At 10,000 monthly views: Monthly: 11.6 kg · Annual: 139.8 kg · ≈ 17472 smartphone charges
D
Carbon Budget
Action
66th percentile
FIX
66th percentile
Warning::
1.16g CO2 — above the median website (0.60g)
Heavier than an estimated 34% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 66th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.16g

66th percentile

Cleaner than 34% of websites

✗ Above the median website

vs Median 94% more
vs Target 133% more
B
Green Hosting
Green (hosting)
REVIEW
Green (hosting)
Info::
Fly.io uses renewable energy
Info::
Fly.io: Carbon offsets for all compute
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 Fly.io✓CDN Not identified✗

Fly.io: Carbon offsets for all compute

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+
Repeat Visit Weight
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 44 KB (vs 5039 KB first visit). 43 of 45 resources are served from browser cache, saving 1.15g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 1.16g)
First visit
5039 KB
Repeat visit
44 KB

99% reduction on repeat visits

Saving 1.15g CO2 per returning visitor

43 resources served from cache · 2 resources re-downloaded

A+
Transfer Efficiency
93% efficient
PASS
93% efficient
Info::
Transfer efficiency: 93%
Only 354 KB of potential savings identified. Your page is well-optimized for size.
93% efficient

Total waste: 354 KB (7% of page weight)

Unused JS 354 KB

0.08g unnecessary CO2 per visit

Actual transfer 5039 KB
Theoretical minimum 4685 KB
Potential savings 354 KB (0.08g 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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