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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
92
GRADE
A
FIX
0
REVIEW
3
PASS
4
INFO
0
Checks
7
4 PASS 3 REVIEW
B
Transfer Efficiency
90% efficient
REVIEW
90% efficient
Info::
Transfer efficiency: 90%
An estimated 85 KB (10%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 85 KB of unused JavaScript. This wasted data produces 0.02g of unnecessary CO2 per page view.
90% efficient

Total waste: 85 KB (10% of page weight)

Unused JS 85 KB

0.02g unnecessary CO2 per visit

Actual transfer 835 KB
Theoretical minimum 750 KB
Potential savings 85 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
0.19g CO2 per view
PASS
0.19g CO2 per view
Info::
0.19g CO2 per page view
This page transfers 0.8 MB, producing an estimated 0.19g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.00g, network 0.04g, end-user device 0.15g.
Got: 0.19g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 23.2 kg CO2/year
With 10,000 page views per month, this page would generate approximately 23.2 kg of CO2 annually — equivalent to charging 2897 smartphones.
Info::
Green hosting reduces data center emissions

0.19g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 90% of websites

Sustainable Web Design model v4 · Page size: 0.8 MB

Your site
0.19g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.00g
Network
0.04g
End-user device
0.15g
At 10,000 monthly views: Monthly: 1.9 kg · Annual: 23.2 kg · ≈ 2897 smartphone charges
A
Green Hosting
Green (cdn)
PASS
Green (cdn)
Info::
Vercel CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
Info::
Vercel: Hosted on AWS/Google Cloud with 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 Hosting✓ Green Hosted
Hosting Next.js✗CDN Vercel✓

Vercel: Hosted on AWS/Google Cloud with renewable energy commitments

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
96% cached
PASS
96% cached
Info::
96% reduction on repeat visits
Returning visitors download only 37 KB (vs 835 KB first visit). 68 of 69 resources are served from browser cache, saving 0.18g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.19g)
First visit
835 KB
Repeat visit
37 KB

96% reduction on repeat visits

Saving 0.18g CO2 per returning visitor

68 resources served from cache · 1 resources re-downloaded

A+
Carbon Budget
10th percentile
PASS
10th percentile
Info::
0.19g 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

0.19g

10th percentile

Cleaner than 90% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 68% cleaner ✓
vs Target 61% 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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