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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
2
PASS
4
INFO
0
Device:
Mobile Desktop
Checks
6
4 PASS 2 REVIEW
B
Transfer Efficiency
76% efficient
REVIEW
76% efficient
Info::
Transfer efficiency: 76%
An estimated 398 KB (24%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 398 KB of unused JavaScript. This wasted data produces 0.09g of unnecessary CO2 per page view.
76% efficient

Total waste: 398 KB (24% of page weight)

Unused JS 398 KB

0.09g unnecessary CO2 per visit

Actual transfer 1644 KB
Theoretical minimum 1246 KB
Potential savings 398 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
CO2 Per Page Load
0.38g CO2 per view
PASS
0.38g CO2 per view
Info::
0.38g CO2 per page view
This page transfers 1.6 MB, producing an estimated 0.38g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.08g, end-user device 0.29g.
Got: 0.38g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 45.6 kg CO2/year
With 10,000 page views per month, this page would generate approximately 45.6 kg of CO2 annually — equivalent to charging 5702 smartphones.
Info::
Green hosting reduces data center emissions

0.38g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 72% of websites

Sustainable Web Design model v4 · Page size: 1.6 MB

Your site
0.38g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.08g
End-user device
0.29g
At 10,000 monthly views: Monthly: 3.8 kg · Annual: 45.6 kg · ≈ 5702 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
95% cached
PASS
95% cached
Info::
95% reduction on repeat visits
Returning visitors download only 86 KB (vs 1644 KB first visit). 79 of 81 resources are served from browser cache, saving 0.36g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 0.38g)
First visit
1644 KB
Repeat visit
86 KB

95% reduction on repeat visits

Saving 0.36g CO2 per returning visitor

79 resources served from cache · 2 resources re-downloaded

A
Carbon Budget
28th percentile
PASS
28th percentile
Info::
0.38g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 72% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 28th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.38g

28th percentile

Cleaner than 72% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 37% cleaner ✓
vs Target 24% 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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