https://www.javalf.com
Sustainability
· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
81
GRADE
B
FIX
2
REVIEW
1
PASS
4
INFO
1
Checks
84 PASS 1 REVIEW 2 FIX
FCO2 Per Page LoadAction1.78g CO2 per viewFIX
CO2 Per Page Load
Action1.78g CO2 per view
1.78g CO2 per view
Warning::
1.78g CO2 per page view
This page transfers 7.5 MB, producing an estimated 1.78g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.04g, network 0.37g, end-user device 1.37g.
Got: 1.78g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 213.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 213.8 kg of CO2 annually — equivalent to charging 26724 smartphones.
Info::
Green hosting reduces data center emissions
1.78g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 17% of websites
Sustainable Web Design model v4 · Page size: 7.5 MB
Your site
1.78g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.04g
Network
0.37g
End-user device
1.37g
At 10,000 monthly views: Monthly: 17.8 kg · Annual: 213.8 kg · ≈ 26724 smartphone charges
FCarbon BudgetAction83th percentileFIX
Carbon Budget
Action83th percentile
83th percentile
Warning::
1.78g CO2 — above the median website (0.60g)
Heavier than an estimated 17% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 83th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
1.78g
83rd percentile
Cleaner than 17% of websites
✗ Above the median website
vs Median 197% more
vs Target 256% more
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.
A+Green HostingGreen (both)PASS
Green Hosting
Green (both)
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Google Cloud, CDN: Fastly
Info::
Google Cloud: Verified by the Green Web Foundation
Info::
Fastly: 100% renewable energy for edge network
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 Google Cloud✓CDN Fastly✓
Google Cloud: Verified by the Green Web Foundation
Fastly: 100% renewable energy for edge network
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 262 KB (vs 7708 KB first visit). 292 of 294 resources are served from browser cache, saving 1.72g CO2 per repeat visit.
Info::
Repeat visit: 0.06g CO2 (first visit: 1.78g)
First visit
7708 KB
Repeat visit
262 KB
97% reduction on repeat visits
Saving 1.72g CO2 per returning visitor
292 resources served from cache · 2 resources re-downloaded
A+Transfer Efficiency96% efficientPASS
Transfer Efficiency
96% efficient
96% efficient
Info::
Transfer efficiency: 96%
Only 326 KB of potential savings identified. Your page is well-optimized for size.
Total waste: 326 KB (4% of page weight)
Unused JS 326 KB
0.08g unnecessary CO2 per visit
Actual transfer 7708 KB
Theoretical minimum 7381 KB
Potential savings 326 KB (0.08g CO2)
See Deep Analysis sections above for specific optimizations.
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: Google Cloud
Image Optimization42 images, 3162 KB total, 204 KB wastedINFO
Image Optimization
42 images, 3162 KB total, 204 KB wasted
Image Optimization Audit
Total Images
42
Total Size
3162 KB
Oversized
3
Wasted
204 KB
38 missing dimensions 28 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.