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

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 Next.js✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

Transfer Efficiency

86% efficient

REVIEW

86% efficient

Transfer efficiency: 86%

An estimated 52 KB (14%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 52 KB of unused JavaScript. This wasted data produces 0.01g of unnecessary CO2 per page view.

Total waste: 52 KB (14% of page weight)

Unused JS 52 KB

0.01g unnecessary CO2 per visit

Actual transfer 376 KB

Theoretical minimum 324 KB

Potential savings 52 KB (0.01g 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

0.10g CO2 per view

PASS

0.10g CO2 per view

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 0.02g, network 0.02g, end-user device 0.07g.

Got: 0.10g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 12.5 kg CO2/year

With 10,000 page views per month, this page would generate approximately 12.5 kg of CO2 annually — equivalent to charging 1562 smartphones.

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

0.02g

Network

0.02g

End-user device

0.07g

At 10,000 monthly views: Monthly: 1.0 kg · Annual: 12.5 kg · ≈ 1562 smartphone charges

A+

Repeat Visit Weight

94% cached

PASS

94% cached

94% reduction on repeat visits

Returning visitors download only 23 KB (vs 376 KB first visit). 14 of 15 resources are served from browser cache, saving 0.10g CO2 per repeat visit.

Repeat visit: 0.01g CO2 (first visit: 0.10g)

First visit

376 KB

Repeat visit

23 KB

94% reduction on repeat visits

Saving 0.10g CO2 per returning visitor

14 resources served from cache · 1 resources re-downloaded

A+

Carbon Budget

10th percentile

PASS

10th percentile

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.

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 79% cleaner ✓

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