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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
73
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
0.90g CO2 per view
FIX
0.90g CO2 per view
Info::
0.90g CO2 per page view
This page transfers 3.8 MB, producing an estimated 0.90g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.19g, end-user device 0.69g.
Got: 0.90g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 107.5 kg CO2/year
With 10,000 page views per month, this page would generate approximately 107.5 kg of CO2 annually — equivalent to charging 13439 smartphones.
Info::
Green hosting reduces data center emissions

0.90g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 42% of websites

Sustainable Web Design model v4 · Page size: 3.8 MB

Your site
0.90g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.02g
Network
0.19g
End-user device
0.69g
At 10,000 monthly views: Monthly: 9.0 kg · Annual: 107.5 kg · ≈ 13439 smartphone charges
D
Carbon Budget
Action
58th percentile
FIX
58th percentile
Warning::
0.90g CO2 — above the median website (0.60g)
Heavier than an estimated 42% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 58th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.90g

58th percentile

Cleaner than 42% of websites

✗ Above the median website

vs Median 49% more
vs Target 79% more
B
Transfer Efficiency
90% efficient
REVIEW
90% efficient
Info::
Transfer efficiency: 90%
An estimated 402 KB (10%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 402 KB of unused JavaScript. This wasted data produces 0.09g of unnecessary CO2 per page view.
90% efficient

Total waste: 402 KB (10% of page weight)

Unused JS 402 KB

0.09g unnecessary CO2 per visit

Actual transfer 3876 KB
Theoretical minimum 3473 KB
Potential savings 402 KB (0.09g 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 Not identified✗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 7 KB (vs 3876 KB first visit). 60 of 61 resources are served from browser cache, saving 0.89g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.90g)
First visit
3876 KB
Repeat visit
7 KB

100% reduction on repeat visits

Saving 0.89g CO2 per returning visitor

60 resources served from cache · 1 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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