Sustainability

· 7 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

Device:

Mobile Desktop

Checks

4 PASS 3 REVIEW

Transfer Efficiency

88% efficient

REVIEW

88% efficient

Transfer efficiency: 88%

An estimated 149 KB (12%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 149 KB of unused JavaScript. This wasted data produces 0.03g of unnecessary CO2 per page view.

Total waste: 149 KB (12% of page weight)

Unused JS 149 KB

0.03g unnecessary CO2 per visit

Actual transfer 1216 KB

Theoretical minimum 1066 KB

Potential savings 149 KB (0.03g CO2)

See Deep Analysis sections above for specific optimizations.

Web Font Weight Variants

No detectable Google Fonts weights

REVIEW

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.

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

CO2 Per Page Load

0.28g CO2 per view

PASS

0.28g CO2 per view

0.28g CO2 per page view

This page transfers 1.2 MB, producing an estimated 0.28g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.06g, end-user device 0.22g.

Got: 0.28g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 33.7 kg CO2/year

With 10,000 page views per month, this page would generate approximately 33.7 kg of CO2 annually — equivalent to charging 4218 smartphones.

Green hosting reduces data center emissions

0.28g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 82% of websites

Sustainable Web Design model v4 · Page size: 1.2 MB

Your site

0.28g

Top 10%

0.20g

Target

0.50g

Median website

0.60g

Energy Breakdown

Data center

0.01g

Network

0.06g

End-user device

0.22g

At 10,000 monthly views: Monthly: 2.8 kg · Annual: 33.7 kg · ≈ 4218 smartphone charges

A+

Green Hosting

Green (both)

PASS

Green (both)

Both hosting and CDN use renewable energy

Got: Hosting: Vercel, CDN: Vercel

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

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 Vercel✓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

96% reduction on repeat visits

Returning visitors download only 50 KB (vs 1216 KB first visit). 44 of 46 resources are served from browser cache, saving 0.27g CO2 per repeat visit.

Repeat visit: 0.01g CO2 (first visit: 0.28g)

First visit

1216 KB

Repeat visit

50 KB

96% reduction on repeat visits

Saving 0.27g CO2 per returning visitor

44 resources served from cache · 2 resources re-downloaded

Carbon Budget

18th percentile

PASS

18th percentile

0.28g CO2 — below the sustainability target of 0.50g

Cleaner than an estimated 82% of websites analyzed. This page meets the Web Sustainability Guidelines target.

Estimated 18th percentile

Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.

Top 10%

Target

Median website

0.28g

18th percentile

Cleaner than 82% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 53% cleaner ✓

vs Target 44% cleaner ✓

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.