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https://zalo.me

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
60
GRADE
D
FIX
3
REVIEW
1
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 1 REVIEW 3 FIX
F
CO2 Per Page Load
Action
1.77g CO2 per view
FIX
1.77g CO2 per view
Warning::
1.77g CO2 per page view
This page transfers 6.3 MB, producing an estimated 1.77g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.33g, network 0.31g, end-user device 1.14g.
Got: 1.77g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 212.7 kg CO2/year
With 10,000 page views per month, this page would generate approximately 212.7 kg of CO2 annually — equivalent to charging 26586 smartphones.

1.77g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 17% of websites

Sustainable Web Design model v4 · Page size: 6.3 MB

Your site
1.77g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.33g
Network
0.31g
End-user device
1.14g
At 10,000 monthly views: Monthly: 17.7 kg · Annual: 212.7 kg · ≈ 26586 smartphone charges
D
Green Hosting
Action
Not green
FIX
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 Next.js✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

F
Carbon Budget
Action
83th percentile
FIX
83th percentile
Warning::
1.77g CO2 — above the median website (0.60g)
Heavier than an estimated 17% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 83th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.77g

83rd percentile

Cleaner than 17% of websites

✗ Above the median website

vs Median 195% more
vs Target 254% more
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Repeat Visit Weight
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 59 KB (vs 6408 KB first visit). 34 of 35 resources are served from browser cache, saving 1.76g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 1.77g)
First visit
6408 KB
Repeat visit
59 KB

99% reduction on repeat visits

Saving 1.76g CO2 per returning visitor

34 resources served from cache · 1 resources re-downloaded

A+
Transfer Efficiency
96% efficient
PASS
96% efficient
Info::
Transfer efficiency: 96%
Only 281 KB of potential savings identified. Your page is well-optimized for size.
96% efficient

Total waste: 281 KB (4% of page weight)

Unused JS 281 KB

0.08g unnecessary CO2 per visit

Actual transfer 6408 KB
Theoretical minimum 6127 KB
Potential savings 281 KB (0.08g CO2)

See Deep Analysis sections above for specific optimizations.

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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