https://backlinko.com
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
73
GRADE
C
FIX
1
REVIEW
3
PASS
2
INFO
0
Checks
62 PASS 3 REVIEW 1 FIX
DTransfer EfficiencyAction51% efficientFIX
Transfer Efficiency
Action51% efficient
51% efficient
Warning::
Transfer efficiency: 51%
An estimated 1057 KB (49%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1057 KB of unused JavaScript. This wasted data produces 0.24g of unnecessary CO2 per page view.
Total waste: 1057 KB (49% of page weight)
Unused JS 1057 KB
0.24g unnecessary CO2 per visit
Actual transfer 2163 KB
Theoretical minimum 1106 KB
Potential savings 1057 KB (0.24g CO2)
See Deep Analysis sections above for specific optimizations.
BCO2 Per Page Load0.50g CO2 per viewREVIEW
CO2 Per Page Load
0.50g CO2 per view
0.50g CO2 per view
Info::
0.50g CO2 per page view
This page transfers 2.1 MB, producing an estimated 0.50g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.10g, end-user device 0.38g.
Got: 0.50g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 60.0 kg CO2/year
With 10,000 page views per month, this page would generate approximately 60.0 kg of CO2 annually — equivalent to charging 7502 smartphones.
Info::
Green hosting reduces data center emissions
0.50g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 60% of websites
Sustainable Web Design model v4 · Page size: 2.1 MB
Your site
0.50g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.01g
Network
0.10g
End-user device
0.38g
At 10,000 monthly views: Monthly: 5.0 kg · Annual: 60.0 kg · ≈ 7502 smartphone charges
BCarbon Budget40th percentileREVIEW
Carbon Budget
40th percentile
40th percentile
Info::
0.50g CO2 — below the median website (0.60g)
Better than an estimated 60% of websites, but above the sustainability target of 0.50g. Reducing page weight would help reach the target.
Info::
Estimated 40th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.50g
40th percentile
Cleaner than 60% of websites
✗ Above the median website
vs Median 17% cleaner ✓
vs Target 0% more
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
AGreen HostingGreen (cdn)PASS
Green Hosting
Green (cdn)
Green (cdn)
Info::
Netlify CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
Info::
Netlify: Hosted on AWS/Google Cloud with renewable energy matching
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 Next.js✗CDN Netlify✓
Netlify: Hosted on AWS/Google Cloud with renewable energy matching
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight98% cachedPASS
Repeat Visit Weight
98% cached
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 38 KB (vs 2163 KB first visit). 104 of 105 resources are served from browser cache, saving 0.49g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.50g)
First visit
2163 KB
Repeat visit
38 KB
98% reduction on repeat visits
Saving 0.49g CO2 per returning visitor
104 resources served from cache · 1 resources re-downloaded
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.