https://oreilly.com
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
64
GRADE
D
FIX
3
REVIEW
1
PASS
2
INFO
0
Checks
62 PASS 1 REVIEW 3 FIX
DCO2 Per Page LoadAction1.24g CO2 per viewFIX
CO2 Per Page Load
Action1.24g CO2 per view
1.24g CO2 per view
Warning::
1.24g CO2 per page view
This page transfers 5.2 MB, producing an estimated 1.24g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.03g, network 0.26g, end-user device 0.95g.
Got: 1.24g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 148.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 148.3 kg of CO2 annually — equivalent to charging 18534 smartphones.
Info::
Green hosting reduces data center emissions
1.24g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 32% of websites
Sustainable Web Design model v4 · Page size: 5.2 MB
Your site
1.24g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.03g
Network
0.26g
End-user device
0.95g
At 10,000 monthly views: Monthly: 12.4 kg · Annual: 148.3 kg · ≈ 18534 smartphone charges
DCarbon BudgetAction68th percentileFIX
Carbon Budget
Action68th percentile
68th percentile
Warning::
1.24g 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
1.24g
68th percentile
Cleaner than 32% of websites
✗ Above the median website
vs Median 106% more
vs Target 147% more
DTransfer EfficiencyAction58% efficientFIX
Transfer Efficiency
Action58% efficient
58% efficient
Warning::
Transfer efficiency: 58%
An estimated 2237 KB (42%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 2237 KB of unused JavaScript. This wasted data produces 0.52g of unnecessary CO2 per page view.
Total waste: 2237 KB (42% of page weight)
Unused JS 2237 KB
0.52g unnecessary CO2 per visit
Actual transfer 5345 KB
Theoretical minimum 3108 KB
Potential savings 2237 KB (0.52g CO2)
See Deep Analysis sections above for specific optimizations.
BGreen HostingGreen (hosting)REVIEW
Green Hosting
Green (hosting)
Green (hosting)
Info::
Apache HTTP Server uses renewable energy
Info::
Apache HTTP Server: Verified by the Green Web Foundation
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 Apache HTTP Server✓CDN Not identified✗
Apache HTTP Server: Verified by the Green Web Foundation
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight99% cachedPASS
Repeat Visit Weight
99% cached
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 42 KB (vs 5345 KB first visit). 117 of 118 resources are served from browser cache, saving 1.23g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 1.24g)
First visit
5345 KB
Repeat visit
42 KB
99% reduction on repeat visits
Saving 1.23g CO2 per returning visitor
117 resources served from cache · 1 resources re-downloaded
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
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.