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https://liftoff.io

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
81
GRADE
B
FIX
0
REVIEW
3
PASS
3
INFO
0
Device:
Mobile Desktop
Checks
6
3 PASS 3 REVIEW
B
Carbon Budget
36th percentile
REVIEW
36th percentile
Info::
0.47g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 64% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 36th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.47g

36th percentile

Cleaner than 64% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 22% cleaner ✓
vs Target 6% cleaner ✓
C
Transfer Efficiency
Action
71% efficient
REVIEW
71% efficient
Warning::
Transfer efficiency: 71%
An estimated 579 KB (29%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 579 KB of unused JavaScript. This wasted data produces 0.13g of unnecessary CO2 per page view.
71% efficient

Total waste: 579 KB (29% of page weight)

Unused JS 579 KB

0.13g unnecessary CO2 per visit

Actual transfer 2029 KB
Theoretical minimum 1450 KB
Potential savings 579 KB (0.13g CO2)

See Deep Analysis sections above for specific optimizations.

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A
CO2 Per Page Load
0.47g CO2 per view
PASS
0.47g CO2 per view
Info::
0.47g CO2 per page view
This page transfers 2.0 MB, producing an estimated 0.47g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.10g, end-user device 0.36g.
Got: 0.47g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 56.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 56.3 kg of CO2 annually — equivalent to charging 7035 smartphones.
Info::
Green hosting reduces data center emissions

0.47g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 64% of websites

Sustainable Web Design model v4 · Page size: 2.0 MB

Your site
0.47g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.10g
End-user device
0.36g
At 10,000 monthly views: Monthly: 4.7 kg · Annual: 56.3 kg · ≈ 7035 smartphone charges
A
Green Hosting
Green (cdn)
PASS
Green (cdn)
Info::
Cloudflare CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
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 Not identified✗CDN Cloudflare✓

Cloudflare: 100% renewable energy for global network since 2019

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
98% cached
PASS
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 30 KB (vs 2029 KB first visit). 155 of 156 resources are served from browser cache, saving 0.46g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.47g)
First visit
2029 KB
Repeat visit
30 KB

98% reduction on repeat visits

Saving 0.46g CO2 per returning visitor

155 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.

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