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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
90
GRADE
A
FIX
0
REVIEW
2
PASS
5
INFO
0
Checks
7
5 PASS 2 REVIEW
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
0.24g CO2 per view
PASS
0.24g CO2 per view
Info::
0.24g CO2 per page view
This page transfers 1.0 MB, producing an estimated 0.24g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.05g, end-user device 0.18g.
Got: 0.24g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 28.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 28.3 kg of CO2 annually — equivalent to charging 3543 smartphones.
Info::
Green hosting reduces data center emissions

0.24g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 87% of websites

Sustainable Web Design model v4 · Page size: 1.0 MB

Your site
0.24g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.05g
End-user device
0.18g
At 10,000 monthly views: Monthly: 2.4 kg · Annual: 28.3 kg · ≈ 3543 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 1022 KB first visit). 79 of 80 resources are served from browser cache, saving 0.23g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.24g)
First visit
1022 KB
Repeat visit
37 KB

96% reduction on repeat visits

Saving 0.23g CO2 per returning visitor

79 resources served from cache · 1 resources re-downloaded

A
Carbon Budget
13th percentile
PASS
13th percentile
Info::
0.24g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 87% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 13th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.24g

13th percentile

Cleaner than 87% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 61% cleaner ✓
vs Target 53% cleaner ✓
A+
Transfer Efficiency
92% efficient
PASS
92% efficient
Info::
Transfer efficiency: 92%
Only 85 KB of potential savings identified. Your page is well-optimized for size.
92% efficient

Total waste: 85 KB (8% of page weight)

Unused JS 85 KB

0.02g unnecessary CO2 per visit

Actual transfer 1022 KB
Theoretical minimum 936 KB
Potential savings 85 KB (0.02g CO2)

See Deep Analysis sections above for specific optimizations.

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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