https://nextjs.org
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
91
GRADE
A
FIX
0
REVIEW
1
PASS
5
INFO
0
Checks
65 PASS 1 REVIEW
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
ActionWhether the site is served from green-energy infrastructure
Green Hosting
No green hosting detected
ACO2 Per Page Load0.31g CO2 per viewPASS
CO2 Per Page Load
0.31g CO2 per view
0.31g CO2 per view
Info::
0.31g CO2 per page view
This page transfers 1.3 MB, producing an estimated 0.31g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.06g, end-user device 0.24g.
Got: 0.31g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 36.9 kg CO2/year
With 10,000 page views per month, this page would generate approximately 36.9 kg of CO2 annually — equivalent to charging 4609 smartphones.
Info::
Green hosting reduces data center emissions
0.31g
Carbon Footprint per page view
✓ Below sustainability target (0.50g)
Cleaner than 80% of websites
Sustainable Web Design model v4 · Page size: 1.3 MB
Your site
0.31g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.01g
Network
0.06g
End-user device
0.24g
At 10,000 monthly views: Monthly: 3.1 kg · Annual: 36.9 kg · ≈ 4609 smartphone charges
AGreen HostingGreen (cdn)PASS
Green Hosting
Green (cdn)
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 Weight97% cachedPASS
Repeat Visit Weight
97% cached
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 37 KB (vs 1329 KB first visit). 121 of 122 resources are served from browser cache, saving 0.30g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.31g)
First visit
1329 KB
Repeat visit
37 KB
97% reduction on repeat visits
Saving 0.30g CO2 per returning visitor
121 resources served from cache · 1 resources re-downloaded
ACarbon Budget20th percentilePASS
Carbon Budget
20th percentile
20th percentile
Info::
0.31g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 80% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 20th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.31g
20th percentile
Cleaner than 80% of websites
✓ Below the Web Sustainability Guidelines target
vs Median 49% cleaner ✓
vs Target 39% cleaner ✓
A+Transfer Efficiency92% efficientPASS
Transfer Efficiency
92% efficient
92% efficient
Info::
Transfer efficiency: 92%
Only 107 KB of potential savings identified. Your page is well-optimized for size.
Total waste: 107 KB (8% of page weight)
Unused JS 107 KB
0.02g unnecessary CO2 per visit
Actual transfer 1329 KB
Theoretical minimum 1221 KB
Potential savings 107 KB (0.02g CO2)
See Deep Analysis sections above for specific optimizations.
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.