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 4 REVIEW

Green Hosting

Green (hosting)

REVIEW

Green (hosting)

Next.js uses renewable energy

Next.js: Verified by the Green Web Foundation

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 Next.js✓CDN Not identified✗

Next.js: Verified by the Green Web Foundation

Based on known provider commitments. Verify at thegreenwebfoundation.org

Carbon Budget

36th percentile

REVIEW

36th percentile

0.47g CO2 — below the sustainability target of 0.50g

Cleaner than an estimated 64% of websites analyzed. This page meets the Web Sustainability Guidelines target.

Estimated 36th percentile

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

Top 10%

Target

Median website

0.47g

36th percentile

Cleaner than 64% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 22% cleaner ✓

vs Target 7% cleaner ✓

Transfer Efficiency

84% efficient

REVIEW

84% efficient

Transfer efficiency: 84%

An estimated 320 KB (16%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 320 KB of unused JavaScript. This wasted data produces 0.07g of unnecessary CO2 per page view.

Total waste: 320 KB (16% of page weight)

Unused JS 320 KB

0.07g unnecessary CO2 per visit

Actual transfer 2013 KB

Theoretical minimum 1693 KB

Potential savings 320 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.

CO2 Per Page Load

0.47g CO2 per view

PASS

0.47g CO2 per view

0.47g CO2 per page view

This page transfers 2.0 MB, producing an estimated 0.47g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.10g, end-user device 0.36g.

Got: 0.47g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 55.9 kg CO2/year

With 10,000 page views per month, this page would generate approximately 55.9 kg of CO2 annually — equivalent to charging 6982 smartphones.

Green hosting reduces data center emissions

0.47g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 64% of websites

Sustainable Web Design model v4 · Page size: 2.0 MB

Your site

0.47g

Top 10%

0.20g

Target

0.50g

Median website

0.60g

Energy Breakdown

Data center

0.01g

Network

0.10g

End-user device

0.36g

At 10,000 monthly views: Monthly: 4.7 kg · Annual: 55.9 kg · ≈ 6982 smartphone charges

A+

Repeat Visit Weight

99% cached

PASS

99% cached

99% reduction on repeat visits

Returning visitors download only 16 KB (vs 2013 KB first visit). 69 of 70 resources are served from browser cache, saving 0.46g CO2 per repeat visit.

Repeat visit: 0.00g CO2 (first visit: 0.47g)

First visit

2013 KB

Repeat visit

16 KB

99% reduction on repeat visits

Saving 0.46g CO2 per returning visitor

69 resources served from cache · 1 resources re-downloaded

A+

Green Hosting

Whether the site is served from green-energy infrastructure

PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: IONOS SE

Image Optimization

3 images, 24 KB total, 11 KB wasted

INFO

Image Optimization Audit

Total Images

Total Size

24 KB

Oversized

Wasted

11 KB

1 missing dimensions

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