https://nextjs.org
Sustainability
· 7 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
5
INFO
0
Checks
75 PASS 2 REVIEW
BWeb Font Weight VariantsNo detectable Google Fonts weightsREVIEW
Web Font Weight Variants
No detectable Google Fonts weights
No detectable Google Fonts weights
Info::
No detectable Google Fonts weights
The analyzer detects font weights via Google Fonts URL parameters (~70% of font-using sites). Self-hosted fonts and non-Google CDN fonts aren't visible to URL-based detection. If you self-host fonts, manually audit how many @font-face weights you ship -- 2-3 weights per family is typically enough; 5+ is usually unused payload.
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 Load0.32g CO2 per viewPASS
CO2 Per Page Load
0.32g CO2 per view
0.32g CO2 per view
Info::
0.32g CO2 per page view
This page transfers 1.3 MB, producing an estimated 0.32g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.07g, end-user device 0.25g.
Got: 0.32g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 38.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 38.3 kg of CO2 annually — equivalent to charging 4791 smartphones.
Info::
Green hosting reduces data center emissions
0.32g
Carbon Footprint per page view
✓ Below sustainability target (0.50g)
Cleaner than 79% of websites
Sustainable Web Design model v4 · Page size: 1.3 MB
Your site
0.32g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.01g
Network
0.07g
End-user device
0.25g
At 10,000 monthly views: Monthly: 3.2 kg · Annual: 38.3 kg · ≈ 4791 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 36 KB (vs 1381 KB first visit). 108 of 109 resources are served from browser cache, saving 0.31g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.32g)
First visit
1381 KB
Repeat visit
36 KB
97% reduction on repeat visits
Saving 0.31g CO2 per returning visitor
108 resources served from cache · 1 resources re-downloaded
ACarbon Budget21th percentilePASS
Carbon Budget
21th percentile
21th percentile
Info::
0.32g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 79% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 21th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.32g
21st percentile
Cleaner than 79% of websites
✓ Below the Web Sustainability Guidelines target
vs Median 47% cleaner ✓
vs Target 36% 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 1381 KB
Theoretical minimum 1274 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.