https://github.com
Sustainability
· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
68
GRADE
D
FIX
3
REVIEW
3
PASS
1
INFO
1
Checks
81 PASS 3 REVIEW 3 FIX
DCO2 Per Page LoadAction1.25g CO2 per viewFIX
CO2 Per Page Load
Action1.25g CO2 per view
1.25g CO2 per view
Warning::
1.25g CO2 per page view
This page transfers 4.4 MB, producing an estimated 1.25g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.23g, network 0.22g, end-user device 0.80g.
Got: 1.25g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 149.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 149.8 kg of CO2 annually — equivalent to charging 18725 smartphones.
1.25g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 32% of websites
Sustainable Web Design model v4 · Page size: 4.4 MB
Your site
1.25g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.23g
Network
0.22g
End-user device
0.80g
At 10,000 monthly views: Monthly: 12.5 kg · Annual: 149.8 kg · ≈ 18725 smartphone charges
DGreen HostingActionNot greenFIX
Green Hosting
ActionNot green
Not green
Info::
No confirmed renewable energy commitment detected
Consider providers like Cloudflare, Google Cloud, or Vercel that match 100% of their energy use with renewables.
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 HostingNot Green Hosted
Hosting Amazon Web Services✗CDN Not identified✗
Based on known provider commitments. Verify at thegreenwebfoundation.org
DCarbon BudgetAction68th percentileFIX
Carbon Budget
Action68th percentile
68th percentile
Warning::
1.25g CO2 — above the median website (0.60g)
Heavier than an estimated 32% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 68th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
1.25g
68th percentile
Cleaner than 32% of websites
✗ Above the median website
vs Median 108% more
vs Target 150% more
BTransfer Efficiency83% efficientREVIEW
Transfer Efficiency
83% efficient
83% efficient
Info::
Transfer efficiency: 83%
An estimated 788 KB (17%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 788 KB of unused JavaScript. This wasted data produces 0.22g of unnecessary CO2 per page view.
Total waste: 788 KB (17% of page weight)
Unused JS 788 KB
0.22g unnecessary CO2 per visit
Actual transfer 4513 KB
Theoretical minimum 3725 KB
Potential savings 788 KB (0.22g 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+Repeat Visit Weight97% cachedPASS
Repeat Visit Weight
97% cached
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 128 KB (vs 4513 KB first visit). 146 of 147 resources are served from browser cache, saving 1.21g CO2 per repeat visit.
Info::
Repeat visit: 0.04g CO2 (first visit: 1.25g)
First visit
4513 KB
Repeat visit
128 KB
97% reduction on repeat visits
Saving 1.21g CO2 per returning visitor
146 resources served from cache · 1 resources re-downloaded
Image Optimization24 images, 101 KB total, 93 KB wastedINFO
Image Optimization
24 images, 101 KB total, 93 KB wasted
Image Optimization Audit
Total Images
24
Total Size
101 KB
Oversized
3
Wasted
93 KB
17 missing alt text 24 missing dimensions
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.