https://bun.sh
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
80
GRADE
B
FIX
1
REVIEW
2
PASS
3
INFO
0
Checks
63 PASS 2 REVIEW 1 FIX
DCarbon BudgetAction54th percentileFIX
Carbon Budget
Action54th percentile
54th percentile
Warning::
0.75g CO2 — above the median website (0.60g)
Heavier than an estimated 46% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 54th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.75g
54th percentile
Cleaner than 46% of websites
✗ Above the median website
vs Median 25% more
vs Target 50% more
BCO2 Per Page Load0.75g CO2 per viewREVIEW
CO2 Per Page Load
0.75g CO2 per view
0.75g CO2 per view
Info::
0.75g CO2 per page view
This page transfers 3.2 MB, producing an estimated 0.75g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.15g, end-user device 0.57g.
Got: 0.75g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 89.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 89.8 kg of CO2 annually — equivalent to charging 11227 smartphones.
Info::
Green hosting reduces data center emissions
0.75g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 46% of websites
Sustainable Web Design model v4 · Page size: 3.2 MB
Your site
0.75g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.02g
Network
0.15g
End-user device
0.57g
At 10,000 monthly views: Monthly: 7.5 kg · Annual: 89.8 kg · ≈ 11227 smartphone charges
BTransfer Efficiency86% efficientREVIEW
Transfer Efficiency
86% efficient
86% efficient
Info::
Transfer efficiency: 86%
An estimated 451 KB (14%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 451 KB of unused JavaScript. This wasted data produces 0.10g of unnecessary CO2 per page view.
Total waste: 451 KB (14% of page weight)
Unused JS 451 KB
0.10g unnecessary CO2 per visit
Actual transfer 3238 KB
Theoretical minimum 2786 KB
Potential savings 451 KB (0.10g CO2)
See Deep Analysis sections above for specific optimizations.
A+Green HostingGreen (both)PASS
Green Hosting
Green (both)
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Vercel, CDN: Cloudflare
Info::
Vercel: Verified by the Green Web Foundation
Info::
Cloudflare: 100% renewable energy for global network since 2019
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 Vercel✓CDN Cloudflare✓
Vercel: Verified by the Green Web Foundation
Cloudflare: 100% renewable energy for global network since 2019
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight98% cachedPASS
Repeat Visit Weight
98% cached
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 60 KB (vs 3238 KB first visit). 51 of 52 resources are served from browser cache, saving 0.73g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.75g)
First visit
3238 KB
Repeat visit
60 KB
98% reduction on repeat visits
Saving 0.73g CO2 per returning visitor
51 resources served from cache · 1 resources re-downloaded
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
Whether the site is served from green-energy infrastructure
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.