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https://nextdoor.com

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
60
GRADE
D
FIX
3
REVIEW
2
PASS
1
INFO
0
Device:
Mobile Desktop
Checks
6
1 PASS 2 REVIEW 3 FIX
D
CO2 Per Page Load
Action
1.17g CO2 per view
FIX
1.17g CO2 per view
Warning::
1.17g CO2 per page view
This page transfers 4.1 MB, producing an estimated 1.17g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.22g, network 0.20g, end-user device 0.75g.
Got: 1.17g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 140.9 kg CO2/year
With 10,000 page views per month, this page would generate approximately 140.9 kg of CO2 annually — equivalent to charging 17606 smartphones.

1.17g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 34% of websites

Sustainable Web Design model v4 · Page size: 4.1 MB

Your site
1.17g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.22g
Network
0.20g
End-user device
0.75g
At 10,000 monthly views: Monthly: 11.7 kg · Annual: 140.9 kg · ≈ 17606 smartphone charges
D
Green Hosting
Action
Not green
FIX
Not green
Info::
No confirmed renewable energy commitment detected
Consider providers like Cloudflare, Google Cloud, or Vercel that match 100% of their energy use with renewables.
Info::
AWS: Renewable energy varies by region; committed to 100% by 2025
Info::
AWS CloudFront: Renewable varies by edge location
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 HostingNot Green Hosted
Hosting AWS✗CDN AWS CloudFront✗

AWS: Renewable energy varies by region; committed to 100% by 2025

AWS CloudFront: Renewable varies by edge location

Based on known provider commitments. Verify at thegreenwebfoundation.org

D
Carbon Budget
Action
66th percentile
FIX
66th percentile
Warning::
1.17g CO2 — above the median website (0.60g)
Heavier than an estimated 34% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 66th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.17g

66th percentile

Cleaner than 34% of websites

✗ Above the median website

vs Median 96% more
vs Target 135% more
C
Transfer Efficiency
Action
65% efficient
REVIEW
65% efficient
Warning::
Transfer efficiency: 65%
An estimated 1490 KB (35%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1490 KB of unused JavaScript. This wasted data produces 0.41g of unnecessary CO2 per page view.
65% efficient

Total waste: 1490 KB (35% of page weight)

Unused JS 1490 KB

0.41g unnecessary CO2 per visit

Actual transfer 4244 KB
Theoretical minimum 2753 KB
Potential savings 1490 KB (0.41g 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+
Repeat Visit Weight
100% cached
PASS
100% cached
Info::
100% reduction on repeat visits
Returning visitors download only 9 KB (vs 4244 KB first visit). 90 of 91 resources are served from browser cache, saving 1.17g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 1.17g)
First visit
4244 KB
Repeat visit
9 KB

100% reduction on repeat visits

Saving 1.17g CO2 per returning visitor

90 resources served from cache · 1 resources re-downloaded

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

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