https://akj.io
Sustainability
· 7 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
95
GRADE
A
FIX
0
REVIEW
3
PASS
4
INFO
0
Checks
74 PASS 3 REVIEW
BTransfer Efficiency84% efficientREVIEW
Transfer Efficiency
84% efficient
84% efficient
Info::
Transfer efficiency: 84%
An estimated 72 KB (16%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 72 KB of unused JavaScript. This wasted data produces 0.02g of unnecessary CO2 per page view.
Total waste: 72 KB (16% of page weight)
Unused JS 72 KB
0.02g unnecessary CO2 per visit
Actual transfer 446 KB
Theoretical minimum 374 KB
Potential savings 72 KB (0.02g CO2)
See Deep Analysis sections above for specific optimizations.
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
A+CO2 Per Page Load0.10g CO2 per viewPASS
CO2 Per Page Load
0.10g CO2 per view
0.10g CO2 per view
Info::
0.10g CO2 per page view
This page transfers 0.4 MB, producing an estimated 0.10g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.00g, network 0.02g, end-user device 0.08g.
Got: 0.10g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 12.4 kg CO2/year
With 10,000 page views per month, this page would generate approximately 12.4 kg of CO2 annually — equivalent to charging 1549 smartphones.
Info::
Green hosting reduces data center emissions
0.10g
Carbon Footprint per page view
✓ Below sustainability target (0.50g)
Cleaner than 90% of websites
Sustainable Web Design model v4 · Page size: 0.4 MB
Your site
0.10g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.00g
Network
0.02g
End-user device
0.08g
At 10,000 monthly views: Monthly: 1.0 kg · Annual: 12.4 kg · ≈ 1549 smartphone charges
A+Green HostingGreen (both)PASS
Green Hosting
Green (both)
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Vercel, CDN: Vercel
Info::
Vercel: Hosted on AWS/Google Cloud with renewable energy commitments
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 Vercel✓CDN Vercel✓
Vercel: Hosted on AWS/Google Cloud with renewable energy commitments
Vercel: Hosted on AWS/Google Cloud with renewable energy commitments
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 8 KB (vs 446 KB first visit). 21 of 22 resources are served from browser cache, saving 0.10g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.10g)
First visit
446 KB
Repeat visit
8 KB
98% reduction on repeat visits
Saving 0.10g CO2 per returning visitor
21 resources served from cache · 1 resources re-downloaded
A+Carbon Budget10th percentilePASS
Carbon Budget
10th percentile
10th percentile
Info::
0.10g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 90% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 10th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.10g
10th percentile
Cleaner than 90% of websites
✓ Below the Web Sustainability Guidelines target
vs Median 83% cleaner ✓
vs Target 79% cleaner ✓
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.