Skip to content
https://redux.js.org

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
93
GRADE
A
FIX
0
REVIEW
2
PASS
4
INFO
0
Device:
Mobile Desktop
Checks
6
4 PASS 2 REVIEW
B
Transfer Efficiency
86% efficient
REVIEW
86% efficient
Info::
Transfer efficiency: 86%
An estimated 50 KB (14%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 50 KB of unused JavaScript. This wasted data produces 0.01g of unnecessary CO2 per page view.
86% efficient

Total waste: 50 KB (14% of page weight)

Unused JS 50 KB

0.01g unnecessary CO2 per visit

Actual transfer 359 KB
Theoretical minimum 308 KB
Potential savings 50 KB (0.01g CO2)

See Deep Analysis sections above for specific optimizations.

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
CO2 Per Page Load
0.08g CO2 per view
PASS
0.08g CO2 per view
Info::
0.08g CO2 per page view
This page transfers 0.4 MB, producing an estimated 0.08g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.00g, network 0.02g, end-user device 0.06g.
Got: 0.08g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 10.0 kg CO2/year
With 10,000 page views per month, this page would generate approximately 10.0 kg of CO2 annually — equivalent to charging 1245 smartphones.
Info::
Green hosting reduces data center emissions

0.08g

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
0.08g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.00g
Network
0.02g
End-user device
0.06g
At 10,000 monthly views: Monthly: 0.8 kg · Annual: 10.0 kg · ≈ 1245 smartphone charges
A
Green Hosting
Green (cdn)
PASS
Green (cdn)
Info::
Netlify CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
Info::
Netlify: Hosted on AWS/Google Cloud with renewable energy matching
Info::
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 Netlify✓

Netlify: Hosted on AWS/Google Cloud with renewable energy matching

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
98% cached
PASS
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 5 KB (vs 359 KB first visit). 41 of 42 resources are served from browser cache, saving 0.08g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.08g)
First visit
359 KB
Repeat visit
5 KB

98% reduction on repeat visits

Saving 0.08g CO2 per returning visitor

41 resources served from cache · 1 resources re-downloaded

A+
Carbon Budget
10th percentile
PASS
10th percentile
Info::
0.08g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 90% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 10th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.08g

10th percentile

Cleaner than 90% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 86% cleaner ✓
vs Target 83% cleaner ✓
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback