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Sustainability

· 7 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
80
GRADE
B
FIX
2
REVIEW
4
PASS
1
INFO
0
Device:
Mobile Desktop
Checks
7
1 PASS 4 REVIEW 2 FIX
D
Green Hosting
Action
Unknown
FIX
Unknown
Info::
Hosting provider could not be identified
Without knowing the provider, we cannot determine their energy sourcing. Check with your hosting provider about their renewable energy commitments.
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 HostingUnable to Determine
Hosting Not identified✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

D
Transfer Efficiency
Action
59% efficient
FIX
59% efficient
Warning::
Transfer efficiency: 59%
An estimated 859 KB (41%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 859 KB of unused JavaScript. This wasted data produces 0.24g of unnecessary CO2 per page view.
59% efficient

Total waste: 859 KB (41% of page weight)

Unused JS 859 KB

0.24g unnecessary CO2 per visit

Actual transfer 2099 KB
Theoretical minimum 1240 KB
Potential savings 859 KB (0.24g CO2)

See Deep Analysis sections above for specific optimizations.

B
CO2 Per Page Load
0.58g CO2 per view
REVIEW
0.58g CO2 per view
Info::
0.58g CO2 per page view
This page transfers 2.1 MB, producing an estimated 0.58g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.11g, network 0.10g, end-user device 0.37g.
Got: 0.58g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 69.7 kg CO2/year
With 10,000 page views per month, this page would generate approximately 69.7 kg of CO2 annually — equivalent to charging 8711 smartphones.

0.58g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 52% of websites

Sustainable Web Design model v4 · Page size: 2.1 MB

Your site
0.58g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.11g
Network
0.10g
End-user device
0.37g
At 10,000 monthly views: Monthly: 5.8 kg · Annual: 69.7 kg · ≈ 8711 smartphone charges
B
Carbon Budget
48th percentile
REVIEW
48th percentile
Info::
0.58g CO2 — below the median website (0.60g)
Better than an estimated 52% of websites, but above the sustainability target of 0.50g. Reducing page weight would help reach the target.
Info::
Estimated 48th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.58g

48th percentile

Cleaner than 52% of websites

✗ Above the median website

vs Median 3% cleaner ✓
vs Target 16% more
B
Web Font Weight Variants
No detectable Google Fonts weights
REVIEW
No detectable Google Fonts weights
Info::
No detectable Google Fonts weights
The analyzer detects font weights via Google Fonts URL parameters (~70% of font-using sites). Self-hosted fonts and non-Google CDN fonts aren't visible to URL-based detection. If you self-host fonts, manually audit how many @font-face weights you ship -- 2-3 weights per family is typically enough; 5+ is usually unused payload.
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Repeat Visit Weight
96% cached
PASS
96% cached
Info::
96% reduction on repeat visits
Returning visitors download only 75 KB (vs 2099 KB first visit). 38 of 39 resources are served from browser cache, saving 0.56g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 0.58g)
First visit
2099 KB
Repeat visit
75 KB

96% reduction on repeat visits

Saving 0.56g CO2 per returning visitor

38 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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