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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
88
GRADE
B
FIX
0
REVIEW
2
PASS
5
INFO
1
Checks
8
5 PASS 2 REVIEW
B
Carbon Budget
38th percentile
REVIEW
38th percentile
Info::
0.48g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 62% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 38th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.48g

38th percentile

Cleaner than 62% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 20% cleaner ✓
vs Target 4% cleaner ✓
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.
A
CO2 Per Page Load
0.48g CO2 per view
PASS
0.48g CO2 per view
Info::
0.48g CO2 per page view
This page transfers 2.0 MB, producing an estimated 0.48g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.10g, end-user device 0.37g.
Got: 0.48g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 57.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 57.8 kg of CO2 annually — equivalent to charging 7220 smartphones.
Info::
Green hosting reduces data center emissions

0.48g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 62% of websites

Sustainable Web Design model v4 · Page size: 2.0 MB

Your site
0.48g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.10g
End-user device
0.37g
At 10,000 monthly views: Monthly: 4.8 kg · Annual: 57.8 kg · ≈ 7220 smartphone charges
A+
Green Hosting
Green (both)
PASS
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: GitHub Pages, CDN: GitHub Pages
Info::
GitHub Pages: Verified by the Green Web Foundation
Info::
GitHub Pages: Hosted on Azure/GitHub with Microsoft carbon-negative commitment
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 GitHub Pages✓CDN GitHub Pages✓

GitHub Pages: Verified by the Green Web Foundation

GitHub Pages: Hosted on Azure/GitHub with Microsoft carbon-negative commitment

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 19 KB (vs 2082 KB first visit). 25 of 26 resources are served from browser cache, saving 0.48g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.48g)
First visit
2082 KB
Repeat visit
19 KB

99% reduction on repeat visits

Saving 0.48g CO2 per returning visitor

25 resources served from cache · 1 resources re-downloaded

A+
Transfer Efficiency
100% efficient
PASS
100% efficient
Info::
Transfer efficiency: 100%
Only 0 KB of potential savings identified. Your page is well-optimized for size.
100% efficient
Actual transfer 2082 KB
Theoretical minimum 2082 KB

See Deep Analysis sections above for specific optimizations.

A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Fastly

Image Optimization
26 images, 537 KB total, 12 KB wasted
INFO

Image Optimization Audit

Total Images

26

Total Size

537 KB

Oversized

1

Wasted

12 KB

2 missing dimensions 2 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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