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Sustainability

· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
81
GRADE
B
FIX
1
REVIEW
4
PASS
2
INFO
1
Device:
Mobile Desktop
Checks
8
2 PASS 4 REVIEW 1 FIX
D
Green Hosting
Action
Not green
FIX
Not green
Info::
No confirmed renewable energy commitment detected
Consider providers like Cloudflare, Google Cloud, or Vercel that match 100% of their energy use with renewables.
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 HostingNot Green Hosted
Hosting Apache Traffic Server✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

B
Repeat Visit Weight
73% cached
REVIEW
73% cached
Info::
73% reduction on repeat visits
Returning visitors download only 148 KB (vs 556 KB first visit). 37 of 38 resources are served from browser cache, saving 0.11g CO2 per repeat visit.
Info::
Repeat visit: 0.04g CO2 (first visit: 0.15g)
First visit
556 KB
Repeat visit
148 KB

73% reduction on repeat visits

Saving 0.11g CO2 per returning visitor

37 resources served from cache · 1 resources re-downloaded

B
Transfer Efficiency
86% efficient
REVIEW
86% efficient
Info::
Transfer efficiency: 86%
An estimated 79 KB (14%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 79 KB of unused JavaScript. This wasted data produces 0.02g of unnecessary CO2 per page view.
86% efficient

Total waste: 79 KB (14% of page weight)

Unused JS 79 KB

0.02g unnecessary CO2 per visit

Actual transfer 556 KB
Theoretical minimum 477 KB
Potential savings 79 KB (0.02g CO2)

See Deep Analysis sections above for specific optimizations.

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+
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 0.5 MB, producing an estimated 0.15g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.03g, network 0.03g, end-user device 0.10g.
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 2309 smartphones.

0.15g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 90% of websites

Sustainable Web Design model v4 · Page size: 0.5 MB

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

Energy Breakdown

Data center
0.03g
Network
0.03g
End-user device
0.10g
At 10,000 monthly views: Monthly: 1.5 kg · Annual: 18.5 kg · ≈ 2309 smartphone charges
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 ✓
Image Optimization
57 images, 600 KB total, 51 KB wasted
INFO

Image Optimization Audit

Total Images

57

Total Size

600 KB

Oversized

13

Wasted

51 KB

22 missing alt text 1 missing dimensions 49 missing lazy loading
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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