https://gitbook.com
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
80
GRADE
B
FIX
2
REVIEW
1
PASS
3
INFO
0
Checks
63 PASS 1 REVIEW 2 FIX
DCO2 Per Page LoadAction0.80g CO2 per viewFIX
CO2 Per Page Load
Action0.80g CO2 per view
0.80g CO2 per view
Info::
0.80g CO2 per page view
This page transfers 3.4 MB, producing an estimated 0.80g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.17g, end-user device 0.62g.
Got: 0.80g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 96.4 kg CO2/year
With 10,000 page views per month, this page would generate approximately 96.4 kg of CO2 annually — equivalent to charging 12053 smartphones.
Info::
Green hosting reduces data center emissions
0.80g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 45% of websites
Sustainable Web Design model v4 · Page size: 3.4 MB
Your site
0.80g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.02g
Network
0.17g
End-user device
0.62g
At 10,000 monthly views: Monthly: 8.0 kg · Annual: 96.4 kg · ≈ 12053 smartphone charges
DCarbon BudgetAction55th percentileFIX
Carbon Budget
Action55th percentile
55th percentile
Warning::
0.80g CO2 — above the median website (0.60g)
Heavier than an estimated 45% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 55th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.80g
55th percentile
Cleaner than 45% of websites
✗ Above the median website
vs Median 34% more
vs Target 61% more
BTransfer Efficiency78% efficientREVIEW
Transfer Efficiency
78% efficient
78% efficient
Info::
Transfer efficiency: 78%
An estimated 778 KB (22%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 778 KB of unused JavaScript. This wasted data produces 0.18g of unnecessary CO2 per page view.
Total waste: 778 KB (22% of page weight)
Unused JS 778 KB
0.18g unnecessary CO2 per visit
Actual transfer 3476 KB
Theoretical minimum 2697 KB
Potential savings 778 KB (0.18g CO2)
See Deep Analysis sections above for specific optimizations.
A+Green HostingGreen (both)PASS
Green Hosting
Green (both)
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Cloudflare, CDN: Cloudflare
Info::
Cloudflare: Verified by the Green Web Foundation
Info::
Cloudflare: 100% renewable energy for global network since 2019
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 Cloudflare✓CDN Cloudflare✓
Cloudflare: Verified by the Green Web Foundation
Cloudflare: 100% renewable energy for global network since 2019
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight96% cachedPASS
Repeat Visit Weight
96% cached
96% cached
Info::
96% reduction on repeat visits
Returning visitors download only 124 KB (vs 3476 KB first visit). 167 of 170 resources are served from browser cache, saving 0.77g CO2 per repeat visit.
Info::
Repeat visit: 0.03g CO2 (first visit: 0.80g)
First visit
3476 KB
Repeat visit
124 KB
96% reduction on repeat visits
Saving 0.77g CO2 per returning visitor
167 resources served from cache · 3 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: Cloudflare
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.