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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
85
GRADE
B
FIX
1
REVIEW
3
PASS
3
INFO
1
Device:
Mobile Desktop
Checks
8
3 PASS 3 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 Next.js✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

B
Transfer Efficiency
88% efficient
REVIEW
88% efficient
Info::
Transfer efficiency: 88%
An estimated 95 KB (12%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 95 KB of unused JavaScript. This wasted data produces 0.03g of unnecessary CO2 per page view.
88% efficient

Total waste: 95 KB (12% of page weight)

Unused JS 95 KB

0.03g unnecessary CO2 per visit

Actual transfer 812 KB
Theoretical minimum 716 KB
Potential savings 95 KB (0.03g 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
0.22g CO2 per view
PASS
0.22g CO2 per view
Info::
0.22g CO2 per page view
This page transfers 0.8 MB, producing an estimated 0.22g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.04g, network 0.04g, end-user device 0.14g.
Got: 0.22g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 27.0 kg CO2/year
With 10,000 page views per month, this page would generate approximately 27.0 kg of CO2 annually — equivalent to charging 3370 smartphones.

0.22g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 88% of websites

Sustainable Web Design model v4 · Page size: 0.8 MB

Your site
0.22g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.04g
Network
0.04g
End-user device
0.14g
At 10,000 monthly views: Monthly: 2.2 kg · Annual: 27.0 kg · ≈ 3370 smartphone charges
A+
Repeat Visit Weight
94% cached
PASS
94% cached
Info::
94% reduction on repeat visits
Returning visitors download only 45 KB (vs 812 KB first visit). 246 of 247 resources are served from browser cache, saving 0.21g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.22g)
First visit
812 KB
Repeat visit
45 KB

94% reduction on repeat visits

Saving 0.21g CO2 per returning visitor

246 resources served from cache · 1 resources re-downloaded

A
Carbon Budget
12th percentile
PASS
12th percentile
Info::
0.22g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 88% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 12th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.22g

12th percentile

Cleaner than 88% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 63% cleaner ✓
vs Target 55% cleaner ✓
Image Optimization
26 images, 9 KB total, 0 KB wasted
INFO

Image Optimization Audit

Total Images

26

Total Size

9 KB

15 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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