https://skyscanner.net
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
1
REVIEW
3
PASS
3
INFO
1
Checks
83 PASS 3 REVIEW 1 FIX
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 Apache HTTP Server✗CDN Not identified✗
Based on known provider commitments. Verify at thegreenwebfoundation.org
CTransfer EfficiencyAction74% efficientREVIEW
Transfer Efficiency
Action74% efficient
74% efficient
Warning::
Transfer efficiency: 74%
An estimated 180 KB (26%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 180 KB of unused JavaScript. This wasted data produces 0.05g of unnecessary CO2 per page view.
Total waste: 180 KB (26% of page weight)
Unused JS 180 KB
0.05g unnecessary CO2 per visit
Actual transfer 683 KB
Theoretical minimum 502 KB
Potential savings 180 KB (0.05g 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 Load0.19g CO2 per viewPASS
CO2 Per Page Load
0.19g CO2 per view
0.19g CO2 per view
Info::
0.19g CO2 per page view
This page transfers 0.7 MB, producing an estimated 0.19g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.04g, network 0.03g, end-user device 0.12g.
Got: 0.19g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 22.7 kg CO2/year
With 10,000 page views per month, this page would generate approximately 22.7 kg of CO2 annually — equivalent to charging 2835 smartphones.
0.19g
Carbon Footprint per page view
✓ Below sustainability target (0.50g)
Cleaner than 90% of websites
Sustainable Web Design model v4 · Page size: 0.7 MB
Your site
0.19g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.04g
Network
0.03g
End-user device
0.12g
At 10,000 monthly views: Monthly: 1.9 kg · Annual: 22.7 kg · ≈ 2835 smartphone charges
A+Repeat Visit Weight99% cachedPASS
Repeat Visit Weight
99% cached
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 3 KB (vs 683 KB first visit). 22 of 25 resources are served from browser cache, saving 0.19g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.19g)
First visit
683 KB
Repeat visit
3 KB
99% reduction on repeat visits
Saving 0.19g CO2 per returning visitor
22 resources served from cache · 3 resources re-downloaded
A+Carbon Budget10th percentilePASS
Carbon Budget
10th percentile
10th percentile
Info::
0.19g 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
0.19g
10th percentile
Cleaner than 90% of websites
✓ Below the Web Sustainability Guidelines target
vs Median 68% cleaner ✓
vs Target 62% cleaner ✓
Image Optimization1 images, 14 KB total, 0 KB wastedINFO
Image Optimization
1 images, 14 KB total, 0 KB wasted
Image Optimization Audit
Total Images
1
Total Size
14 KB
1 missing alt text 1 missing dimensions
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.