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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
80
GRADE
B
FIX
0
REVIEW
4
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 4 REVIEW
B
Repeat Visit Weight
79% cached
REVIEW
79% cached
Info::
79% reduction on repeat visits
Returning visitors download only 441 KB (vs 2104 KB first visit). 72 of 75 resources are served from browser cache, saving 0.38g CO2 per repeat visit.
Info::
Repeat visit: 0.10g CO2 (first visit: 0.49g)
First visit
2104 KB
Repeat visit
441 KB

79% reduction on repeat visits

Saving 0.38g CO2 per returning visitor

72 resources served from cache · 3 resources re-downloaded

B
Carbon Budget
38th percentile
REVIEW
38th percentile
Info::
0.49g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 62% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 38th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.49g

38th percentile

Cleaner than 62% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 19% cleaner ✓
vs Target 3% cleaner ✓
B
Transfer Efficiency
86% efficient
REVIEW
86% efficient
Info::
Transfer efficiency: 86%
An estimated 300 KB (14%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 300 KB of unused JavaScript. This wasted data produces 0.07g of unnecessary CO2 per page view.
86% efficient

Total waste: 300 KB (14% of page weight)

Unused JS 300 KB

0.07g unnecessary CO2 per visit

Actual transfer 2104 KB
Theoretical minimum 1804 KB
Potential savings 300 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
CO2 Per Page Load
0.49g CO2 per view
PASS
0.49g CO2 per view
Info::
0.49g CO2 per page view
This page transfers 2.1 MB, producing an estimated 0.49g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.10g, end-user device 0.37g.
Got: 0.49g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 58.4 kg CO2/year
With 10,000 page views per month, this page would generate approximately 58.4 kg of CO2 annually — equivalent to charging 7295 smartphones.
Info::
Green hosting reduces data center emissions

0.49g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 62% of websites

Sustainable Web Design model v4 · Page size: 2.1 MB

Your site
0.49g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.10g
End-user device
0.37g
At 10,000 monthly views: Monthly: 4.9 kg · Annual: 58.4 kg · ≈ 7295 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

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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