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

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.

Akamai: Committed to 50% renewable by 2030

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 Not identified✗CDN Akamai✗

Akamai: Committed to 50% renewable by 2030

Based on known provider commitments. Verify at thegreenwebfoundation.org

Transfer Efficiency

Action

69% efficient

REVIEW

69% efficient

Transfer efficiency: 69%

An estimated 250 KB (31%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 250 KB of unused JavaScript. This wasted data produces 0.07g of unnecessary CO2 per page view.

Total waste: 250 KB (31% of page weight)

Unused JS 250 KB

0.07g unnecessary CO2 per visit

Actual transfer 810 KB

Theoretical minimum 559 KB

Potential savings 250 KB (0.07g 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

0.22g CO2 per view

PASS

0.22g CO2 per view

0.22g CO2 per page view

This page transfers 0.8 MB, producing an estimated 0.22g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.04g, network 0.04g, end-user device 0.14g.

Got: 0.22g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 26.9 kg CO2/year

With 10,000 page views per month, this page would generate approximately 26.9 kg of CO2 annually — equivalent to charging 3362 smartphones.

0.22g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 88% of websites

Sustainable Web Design model v4 · Page size: 0.8 MB

Your site

0.22g

Top 10%

0.20g

Target

0.50g

Median website

0.60g

Energy Breakdown

Data center

0.04g

Network

0.04g

End-user device

0.14g

At 10,000 monthly views: Monthly: 2.2 kg · Annual: 26.9 kg · ≈ 3362 smartphone charges

A+

Repeat Visit Weight

99% cached

PASS

99% cached

99% reduction on repeat visits

Returning visitors download only 7 KB (vs 810 KB first visit). 22 of 24 resources are served from browser cache, saving 0.22g CO2 per repeat visit.

Repeat visit: 0.00g CO2 (first visit: 0.22g)

First visit

810 KB

Repeat visit

7 KB

99% reduction on repeat visits

Saving 0.22g CO2 per returning visitor

22 resources served from cache · 2 resources re-downloaded

Carbon Budget

12th percentile

PASS

12th percentile

0.22g CO2 — below the sustainability target of 0.50g

Cleaner than an estimated 88% of websites analyzed. This page meets the Web Sustainability Guidelines target.

Estimated 12th percentile

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

Top 10%

Target

Median website

0.22g

12th percentile

Cleaner than 88% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 63% cleaner ✓

vs Target 55% cleaner ✓

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