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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
93
GRADE
A
FIX
0
REVIEW
2
PASS
4
INFO
0
Device:
Mobile Desktop
Checks
6
4 PASS 2 REVIEW
B
Transfer Efficiency
88% efficient
REVIEW
88% efficient
Info::
Transfer efficiency: 88%
An estimated 81 KB (12%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 81 KB of unused JavaScript. This wasted data produces 0.02g of unnecessary CO2 per page view.
88% efficient

Total waste: 81 KB (12% of page weight)

Unused JS 81 KB

0.02g unnecessary CO2 per visit

Actual transfer 666 KB
Theoretical minimum 585 KB
Potential savings 81 KB (0.02g 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+
CO2 Per Page Load
0.15g CO2 per view
PASS
0.15g CO2 per view
Info::
0.15g CO2 per page view
This page transfers 0.7 MB, producing an estimated 0.15g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.00g, network 0.03g, end-user device 0.12g.
Got: 0.15g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 18.5 kg CO2/year
With 10,000 page views per month, this page would generate approximately 18.5 kg of CO2 annually — equivalent to charging 2311 smartphones.
Info::
Green hosting reduces data center emissions

0.15g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 90% of websites

Sustainable Web Design model v4 · Page size: 0.7 MB

Your site
0.15g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.00g
Network
0.03g
End-user device
0.12g
At 10,000 monthly views: Monthly: 1.5 kg · Annual: 18.5 kg · ≈ 2311 smartphone charges
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
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 8 KB (vs 666 KB first visit). 33 of 34 resources are served from browser cache, saving 0.15g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.15g)
First visit
666 KB
Repeat visit
8 KB

99% reduction on repeat visits

Saving 0.15g CO2 per returning visitor

33 resources served from cache · 1 resources re-downloaded

A+
Carbon Budget
10th percentile
PASS
10th percentile
Info::
0.15g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 90% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 10th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.15g

10th percentile

Cleaner than 90% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 74% cleaner ✓
vs Target 69% cleaner ✓
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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