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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
81
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
54th percentile
FIX
54th percentile
Warning::
0.76g CO2 — above the median website (0.60g)
Heavier than an estimated 46% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 54th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.76g

54th percentile

Cleaner than 46% of websites

✗ Above the median website

vs Median 26% more
vs Target 51% more
B
CO2 Per Page Load
0.76g CO2 per view
REVIEW
0.76g CO2 per view
Info::
0.76g CO2 per page view
This page transfers 3.2 MB, producing an estimated 0.76g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.16g, end-user device 0.58g.
Got: 0.76g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 90.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 90.8 kg of CO2 annually — equivalent to charging 11348 smartphones.
Info::
Green hosting reduces data center emissions

0.76g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 46% of websites

Sustainable Web Design model v4 · Page size: 3.2 MB

Your site
0.76g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.02g
Network
0.16g
End-user device
0.58g
At 10,000 monthly views: Monthly: 7.6 kg · Annual: 90.8 kg · ≈ 11348 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 (cdn)
PASS
Green (cdn)
Info::
Fastly CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
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 Next.js✗CDN Fastly✓

Fastly: 100% renewable energy for edge network

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 20 KB (vs 3273 KB first visit). 57 of 59 resources are served from browser cache, saving 0.75g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.76g)
First visit
3273 KB
Repeat visit
20 KB

99% reduction on repeat visits

Saving 0.75g CO2 per returning visitor

57 resources served from cache · 2 resources re-downloaded

A+
Transfer Efficiency
98% efficient
PASS
98% efficient
Info::
Transfer efficiency: 98%
Only 81 KB of potential savings identified. Your page is well-optimized for size.
98% efficient

Total waste: 81 KB (2% of page weight)

Unused JS 81 KB

0.02g unnecessary CO2 per visit

Actual transfer 3273 KB
Theoretical minimum 3191 KB
Potential savings 81 KB (0.02g 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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