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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
88
GRADE
B
FIX
1
REVIEW
1
PASS
5
INFO
0
Checks
7
5 PASS 1 REVIEW 1 FIX
D
Transfer Efficiency
Action
40% efficient
FIX
40% efficient
Critical::
Transfer efficiency: 40%
An estimated 259 KB (60%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 259 KB of unused JavaScript. This wasted data produces 0.06g of unnecessary CO2 per page view.
40% efficient

Total waste: 259 KB (60% of page weight)

Unused JS 259 KB

0.06g unnecessary CO2 per visit

Actual transfer 435 KB
Theoretical minimum 176 KB
Potential savings 259 KB (0.06g 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.
A+
CO2 Per Page Load
0.10g CO2 per view
PASS
0.10g CO2 per view
Info::
0.10g CO2 per page view
This page transfers 0.4 MB, producing an estimated 0.10g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.00g, network 0.02g, end-user device 0.08g.
Got: 0.10g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 12.1 kg CO2/year
With 10,000 page views per month, this page would generate approximately 12.1 kg of CO2 annually — equivalent to charging 1510 smartphones.
Info::
Green hosting reduces data center emissions

0.10g

Carbon Footprint per page view

Below sustainability target (0.50g)

Cleaner than 90% of websites

Sustainable Web Design model v4 · Page size: 0.4 MB

Your site
0.10g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.00g
Network
0.02g
End-user device
0.08g
At 10,000 monthly views: Monthly: 1.0 kg · Annual: 12.1 kg · ≈ 1510 smartphone charges
A+
Green Hosting
Green (both)
PASS
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Cloudflare, CDN: Cloudflare
Info::
Cloudflare: Verified by the Green Web Foundation
Info::
Cloudflare: 100% renewable energy for global network since 2019
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 CloudflareCDN Cloudflare

Cloudflare: Verified by the Green Web Foundation

Cloudflare: 100% renewable energy for global network since 2019

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 6 KB (vs 435 KB first visit). 9 of 10 resources are served from browser cache, saving 0.10g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.10g)
First visit
435 KB
Repeat visit
6 KB

99% reduction on repeat visits

Saving 0.10g CO2 per returning visitor

9 resources served from cache · 1 resources re-downloaded

A+
Carbon Budget
10th percentile
PASS
10th percentile
Info::
0.10g 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

0.10g

10th percentile

Cleaner than 90% of websites

Below the Web Sustainability Guidelines target

vs Median 83% cleaner ✓
vs Target 80% cleaner ✓
A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

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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