Skip to content
https://tailscale.com

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
73
GRADE
C
FIX
1
REVIEW
3
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 3 REVIEW 1 FIX
D
Carbon Budget
Action
52th percentile
FIX
52th percentile
Warning::
0.70g CO2 — above the median website (0.60g)
Heavier than an estimated 48% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 52th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.70g

52nd percentile

Cleaner than 48% of websites

✗ Above the median website

vs Median 16% more
vs Target 39% more
B
CO2 Per Page Load
0.70g CO2 per view
REVIEW
0.70g CO2 per view
Info::
0.70g CO2 per page view
This page transfers 2.9 MB, producing an estimated 0.70g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.14g, end-user device 0.54g.
Got: 0.70g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 83.7 kg CO2/year
With 10,000 page views per month, this page would generate approximately 83.7 kg of CO2 annually — equivalent to charging 10459 smartphones.
Info::
Green hosting reduces data center emissions

0.70g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 48% of websites

Sustainable Web Design model v4 · Page size: 2.9 MB

Your site
0.70g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.02g
Network
0.14g
End-user device
0.54g
At 10,000 monthly views: Monthly: 7.0 kg · Annual: 83.7 kg · ≈ 10459 smartphone charges
C
Transfer Efficiency
Action
74% efficient
REVIEW
74% efficient
Warning::
Transfer efficiency: 74%
An estimated 783 KB (26%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 783 KB of unused JavaScript. This wasted data produces 0.18g of unnecessary CO2 per page view.
74% efficient

Total waste: 783 KB (26% of page weight)

Unused JS 783 KB

0.18g unnecessary CO2 per visit

Actual transfer 3016 KB
Theoretical minimum 2232 KB
Potential savings 783 KB (0.18g 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
Green Hosting
Green (cdn)
PASS
Green (cdn)
Info::
Vercel CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
Info::
Vercel: Hosted on AWS/Google Cloud with renewable energy commitments
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 Next.js✗CDN Vercel✓

Vercel: Hosted on AWS/Google Cloud with renewable energy commitments

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 34 KB (vs 3016 KB first visit). 109 of 110 resources are served from browser cache, saving 0.69g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.70g)
First visit
3016 KB
Repeat visit
34 KB

99% reduction on repeat visits

Saving 0.69g CO2 per returning visitor

109 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.

Send Feedback