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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
55
GRADE
D
FIX
2
REVIEW
2
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 2 REVIEW 2 FIX
F
CO2 Per Page Load
Action
3.71g CO2 per view
FIX
3.71g CO2 per view
Critical::
3.71g CO2 per page view
This page transfers 15.7 MB, producing an estimated 3.71g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.09g, network 0.77g, end-user device 2.85g.
Got: 3.71g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 445.0 kg CO2/year
With 10,000 page views per month, this page would generate approximately 445.0 kg of CO2 annually — equivalent to charging 55622 smartphones.
Info::
Green hosting reduces data center emissions

3.71g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 5% of websites

Sustainable Web Design model v4 · Page size: 15.7 MB

Your site
3.71g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.09g
Network
0.77g
End-user device
2.85g
At 10,000 monthly views: Monthly: 37.1 kg · Annual: 445.0 kg · ≈ 55622 smartphone charges
F
Carbon Budget
Action
95th percentile
FIX
95th percentile
Warning::
3.71g CO2 — above the median website (0.60g)
Heavier than an estimated 5% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 95th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

3.71g

95th percentile

Cleaner than 5% of websites

✗ Above the median website

vs Median 518% more
vs Target 642% more
C
Transfer Efficiency
Action
67% efficient
REVIEW
67% efficient
Warning::
Transfer efficiency: 67%
An estimated 5357 KB (33%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 5357 KB of unused JavaScript. This wasted data produces 1.24g of unnecessary CO2 per page view.
67% efficient

Total waste: 5357 KB (33% of page weight)

Unused JS 5357 KB

1.24g unnecessary CO2 per visit

Actual transfer 16042 KB
Theoretical minimum 10685 KB
Potential savings 5357 KB (1.24g CO2)

See Deep Analysis sections above for specific optimizations.

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
100% cached
PASS
100% cached
Info::
100% reduction on repeat visits
Returning visitors download only 15 KB (vs 16042 KB first visit). 69 of 71 resources are served from browser cache, saving 3.70g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 3.71g)
First visit
16042 KB
Repeat visit
15 KB

100% reduction on repeat visits

Saving 3.70g CO2 per returning visitor

69 resources served from cache · 2 resources re-downloaded

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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