Sustainability

· 8 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

3 PASS 3 REVIEW 1 FIX

Green Hosting

Action

Not green

FIX

Not green

No confirmed renewable energy commitment detected

Consider providers like Cloudflare, Google Cloud, or Vercel that match 100% of their energy use with renewables.

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 HostingNot Green Hosted

Hosting Apache HTTP Server✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

Transfer Efficiency

Action

71% efficient

REVIEW

71% efficient

Transfer efficiency: 71%

An estimated 135 KB (29%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 135 KB of unused JavaScript. This wasted data produces 0.04g of unnecessary CO2 per page view.

Total waste: 135 KB (29% of page weight)

Unused JS 135 KB

0.04g unnecessary CO2 per visit

Actual transfer 469 KB

Theoretical minimum 333 KB

Potential savings 135 KB (0.04g 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

A+

CO2 Per Page Load

0.13g CO2 per view

PASS

0.13g CO2 per view

0.13g CO2 per page view

This page transfers 0.5 MB, producing an estimated 0.13g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.02g, end-user device 0.08g.

Got: 0.13g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 15.6 kg CO2/year

With 10,000 page views per month, this page would generate approximately 15.6 kg of CO2 annually — equivalent to charging 1945 smartphones.

0.13g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 90% of websites

Sustainable Web Design model v4 · Page size: 0.5 MB

Your site

0.13g

Top 10%

0.20g

Target

0.50g

Median website

0.60g

Energy Breakdown

Data center

0.02g

Network

0.02g

End-user device

0.08g

At 10,000 monthly views: Monthly: 1.3 kg · Annual: 15.6 kg · ≈ 1945 smartphone charges

A+

Repeat Visit Weight

90% cached

PASS

90% cached

90% reduction on repeat visits

Returning visitors download only 46 KB (vs 469 KB first visit). 245 of 246 resources are served from browser cache, saving 0.12g CO2 per repeat visit.

Repeat visit: 0.01g CO2 (first visit: 0.13g)

First visit

469 KB

Repeat visit

46 KB

90% reduction on repeat visits

Saving 0.12g CO2 per returning visitor

245 resources served from cache · 1 resources re-downloaded

A+

Carbon Budget

10th percentile

PASS

10th percentile

0.13g CO2 — below the sustainability target of 0.50g

Cleaner than an estimated 90% of websites analyzed. This page meets the Web Sustainability Guidelines target.

Estimated 10th percentile

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

Top 10%

Target

Median website

0.13g

10th percentile

Cleaner than 90% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 78% cleaner ✓

vs Target 74% cleaner ✓

Image Optimization

200 images, 42 KB total, 0 KB wasted

INFO

Image Optimization Audit

Total Images

200

Total Size

42 KB

199 missing dimensions 193 missing lazy loading

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