Sustainability

· 6 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 2 REVIEW

Transfer Efficiency

76% efficient

REVIEW

76% efficient

Transfer efficiency: 76%

An estimated 250 KB (24%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 250 KB of unused JavaScript. This wasted data produces 0.06g of unnecessary CO2 per page view.

Total waste: 250 KB (24% of page weight)

Unused JS 250 KB

0.06g unnecessary CO2 per visit

Actual transfer 1034 KB

Theoretical minimum 784 KB

Potential savings 250 KB (0.06g CO2)

See Deep Analysis sections above for specific optimizations.

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

CO2 Per Page Load

0.24g CO2 per view

PASS

0.24g CO2 per view

0.24g CO2 per page view

This page transfers 1.0 MB, producing an estimated 0.24g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.05g, end-user device 0.18g.

Got: 0.24g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 28.7 kg CO2/year

With 10,000 page views per month, this page would generate approximately 28.7 kg of CO2 annually — equivalent to charging 3585 smartphones.

Green hosting reduces data center emissions

0.24g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 87% of websites

Sustainable Web Design model v4 · Page size: 1.0 MB

Your site

0.24g

Top 10%

0.20g

Target

0.50g

Median website

0.60g

Energy Breakdown

Data center

0.01g

Network

0.05g

End-user device

0.18g

At 10,000 monthly views: Monthly: 2.4 kg · Annual: 28.7 kg · ≈ 3585 smartphone charges

Green Hosting

Green (cdn)

PASS

Green (cdn)

Fastly CDN uses renewable energy

Since most traffic is served through the CDN, the majority of data transfer energy is renewable.

Fastly: 100% renewable energy for edge network

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 Not identified✗CDN Fastly✓

Fastly: 100% renewable energy for edge network

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+

Repeat Visit Weight

94% cached

PASS

94% cached

94% reduction on repeat visits

Returning visitors download only 58 KB (vs 1034 KB first visit). 41 of 42 resources are served from browser cache, saving 0.23g CO2 per repeat visit.

Repeat visit: 0.01g CO2 (first visit: 0.24g)

First visit

1034 KB

Repeat visit

58 KB

94% reduction on repeat visits

Saving 0.23g CO2 per returning visitor

41 resources served from cache · 1 resources re-downloaded

Carbon Budget

13th percentile

PASS

13th percentile

0.24g CO2 — below the sustainability target of 0.50g

Cleaner than an estimated 87% of websites analyzed. This page meets the Web Sustainability Guidelines target.

Estimated 13th percentile

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

Top 10%

Target

Median website

0.24g

13th percentile

Cleaner than 87% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 60% cleaner ✓

vs Target 52% cleaner ✓

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