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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
87
GRADE
B
FIX
0
REVIEW
4
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 4 REVIEW
B
CO2 Per Page Load
0.55g CO2 per view
REVIEW
0.55g CO2 per view
Info::
0.55g CO2 per page view
This page transfers 2.3 MB, producing an estimated 0.55g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.11g, end-user device 0.42g.
Got: 0.55g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 65.6 kg CO2/year
With 10,000 page views per month, this page would generate approximately 65.6 kg of CO2 annually — equivalent to charging 8195 smartphones.
Info::
Green hosting reduces data center emissions

0.55g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 56% of websites

Sustainable Web Design model v4 · Page size: 2.3 MB

Your site
0.55g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.11g
End-user device
0.42g
At 10,000 monthly views: Monthly: 5.5 kg · Annual: 65.6 kg · ≈ 8195 smartphone charges
B
Carbon Budget
44th percentile
REVIEW
44th percentile
Info::
0.55g CO2 — below the median website (0.60g)
Better than an estimated 56% of websites, but above the sustainability target of 0.50g. Reducing page weight would help reach the target.
Info::
Estimated 44th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.55g

44th percentile

Cleaner than 56% of websites

✗ Above the median website

vs Median 9% cleaner ✓
vs Target 9% more
B
Transfer Efficiency
88% efficient
REVIEW
88% efficient
Info::
Transfer efficiency: 88%
An estimated 288 KB (12%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 288 KB of unused JavaScript. This wasted data produces 0.07g of unnecessary CO2 per page view.
88% efficient

Total waste: 288 KB (12% of page weight)

Unused JS 288 KB

0.07g unnecessary CO2 per visit

Actual transfer 2363 KB
Theoretical minimum 2075 KB
Potential savings 288 KB (0.07g 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
93% cached
PASS
93% cached
Info::
93% reduction on repeat visits
Returning visitors download only 162 KB (vs 2363 KB first visit). 85 of 86 resources are served from browser cache, saving 0.51g CO2 per repeat visit.
Info::
Repeat visit: 0.04g CO2 (first visit: 0.55g)
First visit
2363 KB
Repeat visit
162 KB

93% reduction on repeat visits

Saving 0.51g CO2 per returning visitor

85 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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